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Quartz

Quartz crystal cluster from Tibet
General
Category Oxide mineral
Chemical formula Silica (silicon dioxide, SiO2)
Strunz classification 04.DA.05
Dana classification 75.01.03.01
Identification
Color Colorless through various colors to black
Crystal habit 6-sided prism ending in 6-sided pyramid (typical), drusy, fine-grained to microcrystalline, massive
Crystal system α-quartz: trigonal trapezohedral class 3 2; β-quartz: hexagonal 622[1]
Twinning Common Dauphine law, Brazil law and Japan law
Cleavage {0110} Indistinct
Fracture Conchoidal
Tenacity Brittle
Mohs scale hardness 7 – lower in impure varieties
Luster Vitreous – waxy to dull when massive
Streak White
Diaphaneity Transparent to nearly opaque
Specific gravity 2.65; variable 2.59–2.63 in impure varieties
Optical properties Uniaxial (+)
Refractive index nω = 1.543–1.545 nε = 1.552–1.554
Birefringence +0.009 (B-G interval)
Pleochroism None
Melting point 1670 °C (β tridymite) 1713 °C (β cristobalite)[1]
Solubility Insoluble at STP; 1 ppmmass at 400 °C and 500 lb/in2 to 2600 ppmmass at 500 °C and 1500 lb/in2[1]
Other characteristics Piezoelectric, pyroelectric, may be triboluminescent
References [2][3][4][5]
.Quartz is the second most abundant mineral in the Earth's continental crust, after feldspar.^ The drusy cavities containing amethyst and smoky quartz are not confined to pegmatites, though they are most abundant there.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ The frequent occurrence of smoky quartz in association with rare earth and radioactive minerals is very significant, for later it will be indicated that smoky quartz may have been colored through the action of radioactive elements.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

.It is made up of a continuous framework of SiO4 siliconoxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2.^ As a result, two free oxygen atoms and a free silicon atom would be formed.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ The mechanism of the formation of the free silicon may perhaps be pictured in this way: The radiations may remove the four outer electrons from a silicon atom, which would then be equally shared by the two associated oxygen atoms.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ This solution was prepared by producing an electric arc between two bits of silicon held under isobutyl alcohol.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

.There are many different varieties of quartz, several of which are semi-precious gemstones.^ There are many names for different varieties: Cryptocrystalline varieties of quartz are listed separately under Chalcedony , and include agate.
  • Quartz: Quartz mineral information and data. 12 January 2010 1:01 UTC www.mindat.org [Source type: Academic]

^ STANDING POLISHED POINTS All are natural semi-precious gemstones that have been cut & polished into free standing form, creating a beautiful display specimen.

^ It is semi-transparent to transparent through-out its length, and there are more than 20 parallel phantom layers within it passing through the quartz crystal.
  • Quartz Crystals (natural quartz crystals) 25 September 2009 7:53 UTC www.mineralminers.com [Source type: General]

.Especially in Europe and the Middle East, varieties of quartz have been since antiquity the most commonly used minerals in the making of jewelry and hardstone carvings.^ Quartz is the most common mineral found on the surface of the Earth.
  • Quartz: Quartz mineral information and data. 12 January 2010 1:01 UTC www.mindat.org [Source type: Academic]

^ It does make a nice jacare quartz crystal mineral specimen just as it is, although it could also be carved and polished.
  • Quartz Crystals (natural quartz crystals) 25 September 2009 7:53 UTC www.mineralminers.com [Source type: General]

^ It does make a nice mineral specimen just as it is, although it could also be carved and polished on one side leaving the other side covered with natural terminations!
  • Quartz Crystals (natural quartz crystals) 25 September 2009 7:53 UTC www.mineralminers.com [Source type: General]

.The word "quartz" is derived from the German word "quarz", which was imported from Middle High German, "twarc", which originated in Slavic (cf.^ From the German "Quarz", of uncertain origin.
  • Quartz: Quartz mineral information and data. 12 January 2010 1:01 UTC www.mindat.org [Source type: Academic]

Czech tvrdy ("hard"), Polish twardy ("hard"), Russian твёрдый ("hard")), from Old Church Slavonic тврьдъ ("firm"), from Proto-Slavic *tvьrdъ. [6]

Contents

Crystal habit

Crystal structure of α-quartz
β-quartz
.Quartz belongs to the trigonal crystal system.^ The abundant occurrence of trigonal trapezohedrons and bipyramids upon smoky quartz crystals is testified to by numerous citations in the literature.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

.The ideal crystal shape is a six-sided prism terminating with six-sided pyramids at each end.^ The terminations on the opposite side have a milky quartz skin about an inch thick that make it difficult to see into the crystal when placed in other positions.
  • Quartz Crystals (natural quartz crystals) 25 September 2009 7:53 UTC www.mineralminers.com [Source type: General]

^ It has multiple stepped pyramidal terminations and multiple parallel prismatic faces with some mica and feldspar on one side.
  • Quartz Crystals (natural quartz crystals) 25 September 2009 7:53 UTC www.mineralminers.com [Source type: General]

^ It has a relatively flat shape, and it was attached to other natural jacare elestial crystals on its back side.
  • Quartz Crystals (natural quartz crystals) 25 September 2009 7:53 UTC www.mineralminers.com [Source type: General]

.In nature quartz crystals are often twinned, distorted, or so intergrown with adjacent crystals of quartz or other minerals as to only show part of this shape, or to lack obvious crystal faces altogether and appear massive.^ Natural Quartz Crystal (rock crystal) Jewelry .
  • Quartz Crystals (natural quartz crystals) 25 September 2009 7:53 UTC www.mineralminers.com [Source type: General]

^ Natural Quartz Crystal (rock crystal) Mineral Specimens .
  • Quartz Crystals (natural quartz crystals) 25 September 2009 7:53 UTC www.mineralminers.com [Source type: General]

^ Item : 5.6 inch Natural Quartz Crystal .
  • Quartz Crystals (natural quartz crystals) 25 September 2009 7:53 UTC www.mineralminers.com [Source type: General]

.Well-formed crystals typically form in a 'bed' that has unconstrained growth into a void, but because the crystals must be attached at the other end to a matrix, only one termination pyramid is present.^ Additionally a bed is a common form, particularly for varieties such as amethyst, where the crystals grow up from a matrix and thus only one termination pyramid is present.

^ Because quartz crystallizes into well formed crystals in all its other macroscopic varieties.
  • Information about Rose Quartz and links to rose quartz gems,gemstones and Jewelry 11 October 2009 10:51 UTC www.minerals-n-more.com [Source type: FILTERED WITH BAYES]

^ Crystals that typically form in a 'bed' that has unconstrained growth into a special void or pocket, these crystals are attached at the other end to a matrix, with only one termination present.
  • Quartz crystal cabochon stones for the jewelry professional, spiritualist and hobbyists for sale at Aztec Moon. 12 January 2010 1:01 UTC aztecmoon.com [Source type: FILTERED WITH BAYES]

.A quartz geode is such a situation where the void is approximately spherical in shape, lined with a bed of crystals pointing inward.^ Quartz crystals with this shape are popularly referred to as laser crystals.
  • Quartz Crystals (natural quartz crystals) 25 September 2009 7:53 UTC www.mineralminers.com [Source type: General]

^ The largest crystals in this commercial grade quartz cluster measure about 3.5 inches long, and many of the crystal tips do have damaged points.
  • Quartz Crystals (natural quartz crystals) 25 September 2009 7:53 UTC www.mineralminers.com [Source type: General]

^ Quartz crystals with this shape are popularly referred to as laser quartz crystals.
  • Quartz Crystals (natural quartz crystals) 25 September 2009 7:53 UTC www.mineralminers.com [Source type: General]

.At surface temperatures and pressures, quartz is the most stable form of silicon dioxide.^ It is obvious that amethyst is formed under a greater temperature and pressure range, both higher and lower, than smoky quartz, and that the two types may form simultaneously through a considerable variation in temperature and pressure, as frequently happens.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ It is shown that amethyst and smoky quartz were crystallized from hot aqueous solutions in cavities, under less pressure than normal for the depth at which they were formed, and in a temperature range of about 110-220 for smoky quartz, and 90-250 for amethyst.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ CRYSTALLOGRAPHIC EVIDENCE - Wright and Larsen 10 have indicated criteria which may be used to distinguish quartz formed above 575 from quartz formed below that temperature.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

Quartz will remain stable up to 573 °C at 1 kilobar of pressure. .As the pressure increases the temperature at which quartz will lose stability also increases.^ The following table shows the time necessary for complete decolorization of smoky quartz at various temperatures, or for attaining a pale but stable color.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ It appeared that both the temperature and pressure under which a specimen of quartz was formed could be approximately determined if the mineral contained both water and carbon dioxide inclusions.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ TABLE IV. TEMPERATURE (t) AND PRESSURE. (p) OF FORMATION OF SMOKY QUARTZ AND AMETHYST AS DETERMINED FROM THEIR LIQUID AND GASEOUS INCLUSIONS .
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

.Above 1300 °C and at a pressure of approximately 35 kilobars, only β-quartz is stable.^ It appeared that both the temperature and pressure under which a specimen of quartz was formed could be approximately determined if the mineral contained both water and carbon dioxide inclusions.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

The latter is not the same as normal quartz (or α-quartz), low quartz or just quartz. β-quartz has higher symmetry, is less dense and has a slightly lower specific gravity. .The conversion, from one solid substance to another solid substance, of quartz to β-quartz is quick, reversible and accompanied with a slight energy absorption.^ Various investigators have suggested that smoky quartz is colored in one or another of the following manners: .
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

.The conversion is so easily accomplished that when a crystal of quartz is heated to β-quartz, cooled back down, heated again to β-quartz, etc., then when all is done the quartz will be the same as when it started.^ Back to Quartz Hill, CA housing info , Los Angeles County , California , CA smaller cities , CA small cities , All Cities .
  • Quartz Hill, California (CA 93536) profile: population, maps, real estate, averages, homes, statistics, relocation, travel, jobs, hospitals, schools, crime, moving, houses, sex offenders, news 12 January 2010 1:01 UTC www.city-data.com [Source type: FILTERED WITH BAYES]

The reason that the conversion is so easily accomplished is that the difference between quartz and β-quartz is relatively slight. .The bonds between the oxygen and silicon atoms are "kinked" or bent in quartz and are not so "kinked" in β-quartz.^ The decolorization of smoky quartz by heat can be explained as being due to the oxidation of silicon atoms, causing them to revert to their original character as parts of the quartz lattice.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ As a result, two free oxygen atoms and a free silicon atom would be formed.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ Hence, they should act as small inclusions, the silicon atoms producing the light-scattering and the color so characteristic of smoky quartz.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

At the higher temperatures the atoms move away from each other just enough to allow the bonds to unkink or straighten and produce the higher symmetry. .As the temperature is lowered, the atoms close in on each other and the bonds must kink in order to be stable and this lowers the symmetry back down again.^ The amethyst crystal in question must undoubtedly have formed at a temperature and pressure falling at some point on the curve, but one quantity must be known if the other is to be found.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

.Although all quartz at temperatures lower than 573 °C is low quartz, there are a few examples of crystals that obviously started out as β-quartz.^ A few occurrences of amethyst and smoky quartz in calcareous rocks, sandstones, and quartzites, in which there was no known genetic connection with igneous rocks, have been reported.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ It is shown that amethyst and smoky quartz were crystallized from hot aqueous solutions in cavities, under less pressure than normal for the depth at which they were formed, and in a temperature range of about 110-220 for smoky quartz, and 90-250 for amethyst.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ In k , the temperature is greater than 31, when all the CO 2 is gaseous.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

.Sometimes these are labeled as β-quartz but are actually examples of pseudomorphic or "falsely shaped" crystals more correctly labeled 'quartz after β-quartz'. These crystals are of higher symmetry than low quartz although low quartz can form similar crystals to them.^ It is shown that amethyst and smoky quartz were crystallized from hot aqueous solutions in cavities, under less pressure than normal for the depth at which they were formed, and in a temperature range of about 110-220 for smoky quartz, and 90-250 for amethyst.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ If the present altitude of the occurrences represents the proportional depth of the quartz when it was formed, the temperature of the veins now at 1400 m., would at that time have been 45 more than that of the veins now at 2900 m., assuming an added temperature of 1 for each increment of 33 m.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ The amount of UO 3 indicated by these analyses is about fifty times greater than that ordinarily found in colorless quartz.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

.They are composed of hexagonal dipyramids which are a pair of opposing six sided pyramids and the crystals lack prism faces.^ It has multiple stepped pyramidal terminations and multiple parallel prismatic faces with some mica and feldspar on one side.
  • Quartz Crystals (natural quartz crystals) 25 September 2009 7:53 UTC www.mineralminers.com [Source type: General]

.Quartz's typical termination is composed of two sets of three rhombic faces that can look like a six sided pyramid.^ The terminations on the opposite side have a milky quartz skin about an inch thick that make it difficult to see into the crystal when placed in other positions.
  • Quartz Crystals (natural quartz crystals) 25 September 2009 7:53 UTC www.mineralminers.com [Source type: General]

^ The prismatic faces and terminations of this natural jacare quartz specimen are in mostly good condition with some abraded areas.
  • Quartz Crystals (natural quartz crystals) 25 September 2009 7:53 UTC www.mineralminers.com [Source type: General]

^ This natural quartz crystal has 100% natural prismatic faces and terminations.
  • Quartz Crystals (natural quartz crystals) 25 September 2009 7:53 UTC www.mineralminers.com [Source type: General]

Varieties (according to color)

Citrine
.Pure quartz, traditionally called rock crystal (sometimes called clear quartz), is colorless and transparent (clear) or translucent.^ Natural Quartz Crystal (rock crystal) Gemstones .
  • Quartz Crystals (natural quartz crystals) 25 September 2009 7:53 UTC www.mineralminers.com [Source type: General]

^ Natural Quartz Crystal (rock crystal) Jewelry .
  • Quartz Crystals (natural quartz crystals) 25 September 2009 7:53 UTC www.mineralminers.com [Source type: General]

^ Natural Quartz Crystal (rock crystal) Polished Crystals .
  • Quartz Crystals (natural quartz crystals) 25 September 2009 7:53 UTC www.mineralminers.com [Source type: General]

.Common colored varieties include citrine, rose quartz, amethyst, smoky quartz, milky quartz, and others.^ Intergrowths of smoky quartz and amethyst are frequent.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ Color smoky quartz and amethyst .
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ The occurrence and genesis of smoky quartz and amethyst.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

.Quartz goes by an array of different names.^ Quartz goes by an array of different names.
  • Quartz Destin by G & L Marble - What is Quartz? 12 January 2010 1:01 UTC quartzdestin.com [Source type: FILTERED WITH BAYES]

^ There are many names for different varieties: Cryptocrystalline varieties of quartz are listed separately under Chalcedony , and include agate.
  • Quartz: Quartz mineral information and data. 12 January 2010 1:01 UTC www.mindat.org [Source type: Academic]

^ There are literally hundreds of different names given to Quartz and Chalcedony .
  • The mineral quartz 12 January 2010 1:01 UTC www.minerals.net [Source type: FILTERED WITH BAYES]

.The most important distinction between types of quartz is that of macrocrystalline (individual crystals visible to the unaided eye) and the microcrystalline or cryptocrystalline varieties (aggregates of crystals visible only under high magnification).^ There are many names for different varieties: Cryptocrystalline varieties of quartz are listed separately under Chalcedony , and include agate.
  • Quartz: Quartz mineral information and data. 12 January 2010 1:01 UTC www.mindat.org [Source type: Academic]

^ The fragment of quartz under examination was placed in a bath of melted paraffine, contained in a crystallizing dish on a microscope stage.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ Great color & translucence 5" high & up $140.00/lb Quartz Crystal: Nice and clear, some with rainbows/feathering 2"-3" high .

.The cryptocrystalline varieties are either translucent or mostly opaque, while the transparent varieties tend to be macrocrystalline.^ Diaphaneity is transparent to translucent to opaque.
  • -=[ Alkali-NUTS - MSH - Quartz ]=- 12 January 2010 1:01 UTC www.saint-hilaire.ca [Source type: Academic]

^ The cryptocrystalline varieties are either translucent or mostly opaque, while the transparent varieties tend to be macrocrystalline.
  • Quartz Destin by G & L Marble - What is Quartz? 12 January 2010 1:01 UTC quartzdestin.com [Source type: FILTERED WITH BAYES]

^ The transparent variety tends to be macrocrystalline and the cryptocrystalline varieties are either translucent or mostly opaque.
  • Quartz Mineral,Quartz Mineral Information,Quartz Suppliers,Quartz Mineral Uses 12 January 2010 1:01 UTC www.mineralszone.com [Source type: Reference]

.Chalcedony is a cryptocrystalline form of silica consisting of fine intergrowths of both quartz, and its monoclinic polymorph moganite.^ IN HYDROTHERMAL VEINS CLOSELY ASSOCIATED WITH GRANITES AND PEGMATITES - These quartz veins were formed by the silica-bearing aqueous solutions which were the last differentiation products of acidic magmas.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ With too great a concentration of silica the cryptocrystalline or poorly crystallized varieties of quartz are likely to be formed.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ It appeared that both the temperature and pressure under which a specimen of quartz was formed could be approximately determined if the mineral contained both water and carbon dioxide inclusions.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

[7] .Other opaque gemstone varieties of quartz, or mixed rocks including quartz, often including contrasting bands or patterns of color, are agate, sard, onyx, carnelian, heliotrope, and jasper.^ Natural Quartz Crystal (rock crystal) Gemstones .
  • Quartz Crystals (natural quartz crystals) 25 September 2009 7:53 UTC www.mineralminers.com [Source type: General]

^ ZONAL COLORING - Both of these varieties of quartz are very often zonally colored.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ Only very pale varieties occur elsewhere than in acid igneous rocks, which are much more radioactive than other types of rocks.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

Citrine

Smokey quartz
.Citrine is a variety of quartz whose color ranges from a pale yellow to brown.^ Location: Mined in Minas Gerais, Brazil Price: $1631.00 This naturally terminated quartz crystal has natural medium golden internal color (natural color golden citrine)!
  • Quartz Crystals (natural quartz crystals) 25 September 2009 7:53 UTC www.mineralminers.com [Source type: General]

^ However, naturally colorless quartz rarely becomes violet when radiated, but usually takes on a smoky brown coloration.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ The pleochroism of rock crystal which had been colored brown by radium radiations was found to be identical with that of natural smoky quartz.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

It is nearly impossible to tell cut citrine from yellow topaz visibly. .Citrine has ferric impurities, and is rarely found naturally.^ The transmissibility of a colloidal hydrous ferric oxide solution was measured (curve 4c ) and found to be entirely similar to that of citrine.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

.Most commercial citrine is in fact artificially heated amethyst or smoky quartz.^ Intergrowths of smoky quartz and amethyst are frequent.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ Color smoky quartz and amethyst .
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ The occurrence and genesis of smoky quartz and amethyst.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

.Brazil is the leading producer of citrine, with much of its production coming from the state of Rio Grande do Sul.^ CITRINE (Brazil) from Rio Grande Do Sul and heat treated.

The name is derived from Latin citrina which means "yellow" and is also the origin of the word "citron." [8]
Citrine is one of three traditional birthstones for the month of November.

Rose quartz

An elephant carved in rose quartz, 4 inches (10 cm) long
.Rose quartz is a type of quartz which exhibits a pale pink to rose red hue.^ Rose Quartz rough (Madagascar) Gemmy quality with good pink color in smaller sizes approx.

^ Rose Quartz Hearts (Madagascar) Puff shape 1 1/2" x 1 1/2" size $4.00 each Small puffy hearts in assorted types of stone such as Hematite, Agate, Bloodstone, etc.

^ Furthermore, rose quartz, the color of which is probably due to manganese, 29 is pink, and its color is not deepened by radium radiations as is that of amethyst.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

.The color is usually considered as due to trace amounts of titanium, iron, or manganese, in the massive material.^ It is not generally accepted that the color is due to manganese.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ In amethyst the dichroism is less uniform than in smoky quartz, due to the usual zoning of the colors.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ The analyses in Table XIII show that amethyst contains large amounts of iron, and that the percentage of Fe 2 O 3 decreases quite regularly as the specimens become paler in color.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

.Some rose quartz contains microscopic rutile needles which produces an asterism in transmitted light.^ Hence, they should act as small inclusions, the silicon atoms producing the light-scattering and the color so characteristic of smoky quartz.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ An examination of the specimens of smoky quartz showed in many cases minute needle-like inclusions, which are believed to be rutile, accounting for the presence of titanium in smoky quartz.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ Some observations made during the present study verify Vanzetti's experiments on smoky quartz The scattering of light from quartz was found to be of three types: .
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

.Recent X-ray diffraction studies suggest that the color is due to thin microscopic fibers of possibly dumortierite within the massive quartz.^ In amethyst the dichroism is less uniform than in smoky quartz, due to the usual zoning of the colors.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ These facts suggest that the pigmenting of natural smoky quartz is due to the radiation of colorless quartz by radioactive substances in the solutions from which it formed.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ Furthermore, rose quartz, the color of which is probably due to manganese, 29 is pink, and its color is not deepened by radium radiations as is that of amethyst.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

[9]
.In crystal form (rarely found) it is called pink quartz and its color is thought to be caused by trace amounts of phosphate or aluminium.^ Rose Quartz rough (Madagascar) Gemmy quality with good pink color in smaller sizes approx.

^ The analyses given in Table X shows that the small amount of titanium found in smoky quartz is quite uniform from the darker to the paler specimens.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ This natural quartz crystal has very light smoky color at its base and becomes colorless towards the tip.
  • Quartz Crystals (natural quartz crystals) 25 September 2009 7:53 UTC www.mineralminers.com [Source type: General]

The color in crystals is apparently photosensitive and subject to fading. .The first crystals were found in a pegmatite found near Rumford, Maine, USA, but most crystals on the market come from Minas Gerais, Brazil.^ It was polished from a natural quartz crystal mined in Minas Gerais, Brazil.
  • Quartz Crystals (natural quartz crystals) 25 September 2009 7:53 UTC www.mineralminers.com [Source type: General]

^ Code#: rkxp310 Size: 5.6" tall x 2.9" wide x 2.9" Location: Polished from a natural elestial quartz crystal mined at Minas Gerais, Brazil Price: $54.50 This polished elestial quartz crystal stands up 5.6 inches with its wood base, the crystal measures 4.3" x 1.1" x 1".
  • Quartz Crystals (natural quartz crystals) 25 September 2009 7:53 UTC www.mineralminers.com [Source type: General]

^ Code#: rkxp315 Weight: 3.7 Lbs Size: 7.6" tall x 3.1" wide x 3.1" Location: Polished from a natural elestial quartz crystal mined in Minas Gerais, Brazil Price: $334.50 This elestial quartz crystal stands up 7.6 inches tall and weighs 3.7 pounds.
  • Quartz Crystals (natural quartz crystals) 25 September 2009 7:53 UTC www.mineralminers.com [Source type: General]

[10]
Rose quartz is not popular as a gem – it is generally too clouded by impurities to be suitable for that purpose. .Rose quartz is more often carved into figures such as people or hearts.^ Smoky Quartz: Large with good color Translucent 5"-14" high $40.00 to $60.00/lb Also Rose Quartz "Flames" Graceful arching twist carved into the standing point to resemble a flame.

^ Rose Quartz Hearts (Madagascar) Puff shape 1 1/2" x 1 1/2" size $4.00 each Small puffy hearts in assorted types of stone such as Hematite, Agate, Bloodstone, etc.

^ Furthermore, amethyst contains approximately as much titanium as smoky quartz (Table XIII) and rose quartz considerably more.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

.Hearts are commonly found because rose quartz is pink and an affordable mineral.^ Rose Quartz rough (Madagascar) Gemmy quality with good pink color in smaller sizes approx.

^ Rose Quartz Hearts (Madagascar) Puff shape 1 1/2" x 1 1/2" size $4.00 each Small puffy hearts in assorted types of stone such as Hematite, Agate, Bloodstone, etc.

^ Furthermore, rose quartz, the color of which is probably due to manganese, 29 is pink, and its color is not deepened by radium radiations as is that of amethyst.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

Amethyst

Amethyst. Magaliesburg, South Africa
.Amethyst is a popular form of quartz that ranges from a bright to dark or dull purple color.^ Color smoky quartz and amethyst .
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ In amethyst the dichroism is less uniform than in smoky quartz, due to the usual zoning of the colors.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ Amethyst (Brazil) Dark color- rich purple $15.00/lb Andalusite - Dusty Rose color with dark gray cross pattern $24.00/lb Apache Tears - Black.

Smoky quartz

Smoky quartz is a gray, translucent version of quartz. It ranges in clarity from almost complete transparency to a brownish-gray crystal that is almost opaque. Some can also be black.

Milky quartz

Milky quartz sample
Ancient Roman cameo onyx engraved gem of Augustus
.Milk quartz or milky quartz may be the most common variety of crystalline quartz and can be found almost anywhere.^ Most of the measurements for smoky quartz agree closely with those of the other two varieties.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

.The white color may be caused by minute fluid inclusions of gas, liquid, or both, trapped during the crystal formation.^ When the first together with either the second or third types of inclusions occur in the same specimen, both the temperature and pressure at the time of formation are easily determinable.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ INCLUSIONS CONSISTING ENTIRELY OF CARBON DIOXIDE - Below the critical temperature, 31, these frequently contain both the liquid and gaseous phases.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ The ideas which have been advanced as to the cause of the color of amethyst are very similar, and may be classified as follows: .
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

The cloudiness caused by the inclusions effectively bars its use in most optical and quality gemstone applications.[11]

Varieties (according to microstructure)

.Although many of the varietal names historically arose from the color of the mineral, current scientific naming schemes refer primarily to the microstructure of the mineral.^ Although many of the varietal names historically arose from the color of the mineral, current scientific naming schemes refer primarily to the microstructure of the mineral.
  • Quartz Destin by G & L Marble - What is Quartz? 12 January 2010 1:01 UTC quartzdestin.com [Source type: FILTERED WITH BAYES]

^ Different names are given to quartz based on microstructure of the mineral and color.
  • Quartz Pictures 12 January 2010 1:01 UTC www.jewelinfo4u.com [Source type: FILTERED WITH BAYES]

^ Variety of names arose from the color of the mineral.
  • Quartz Stone, Granite Countertops, Marble Countertops, Granite Rock Tops, Marble countertop, Granite colors, Granite vanity tops, Marble vanity tops, Natural Stone 12 January 2010 1:01 UTC www.graniterocktops.com [Source type: FILTERED WITH BAYES]

.Color is a secondary identifier for the cryptocrystalline minerals, although it is a primary identifier for the macrocrystalline varieties.^ Color is a secondary identifier for the cryptocrystalline minerals, although it is a primary identifier for the macrocrystalline varieties.
  • Quartz Destin by G & L Marble - What is Quartz? 12 January 2010 1:01 UTC quartzdestin.com [Source type: FILTERED WITH BAYES]

^ For the macro-crystalline variety, color is the primary identifier and for cryptocrystalline minerals, color is the secondary identifier.
  • Quartz Stone, Granite Countertops, Marble Countertops, Granite Rock Tops, Marble countertop, Granite colors, Granite vanity tops, Marble vanity tops, Natural Stone 12 January 2010 1:01 UTC www.graniterocktops.com [Source type: FILTERED WITH BAYES]

^ The variety of chalcedonies is even greater than that of transparent quartz, including cryptocrystalline quartz with patterns as well as a wide range of solid colors.

.This does not always hold true.^ This does not always hold true.
  • Quartz Destin by G & L Marble - What is Quartz? 12 January 2010 1:01 UTC quartzdestin.com [Source type: FILTERED WITH BAYES]

Major varieties of quartz
Chalcedony Cryptocrystalline quartz and moganite mixture. The term is generally only used for white or lightly colored material. Otherwise more specific names are used.
Agate Multi-colored, banded chalcedony, semi-translucent to translucent
Onyx Agate where the bands are straight, parallel and consistent in size.
Jasper Opaque cryptocrystalline quartz, typically red to brown
Aventurine Translucent chalcedony with small inclusions (usually mica) that shimmer.
Tiger's Eye Fibrous gold to red-brown colored quartz, exhibiting chatoyancy.
Rock crystal Clear, colorless
Amethyst Purple, transparent
Citrine Yellow to reddish orange to brown, greenish yellow
Prasiolite Mint green, transparent
Rose quartz Pink, translucent, may display diasterism
Rutilated quartz Contains acicular (needles) inclusions of rutile
Milk quartz White, translucent to opaque, may display diasterism
Smoky quartz Brown to gray, opaque
Carnelian Reddish orange chalcedony, translucent

Synthetic and artificial treatments

A synthetic quartz crystal grown by the hydrothermal method, about 19 cm long and weighing about 127 grams
Not all varieties of quartz are naturally occurring. .Prasiolite, an olive colored material, is produced by heat treatment; natural prasiolite has also been observed in Lower Silesia in Poland.^ EGOROFF, N. Dichroism produced by radium in colorless quartz, and a thermo-electric effect observed on the colored striae.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ Rapidly increasing time is required to discharge the color as the temperature of heating is lowered.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ Furthermore, the zonal coloring observed in natural crystals is often duplicated in the radiated rock crystal.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

.Although citrine occurs naturally, the majority is the result of heat-treated amethyst.^ Nabl (20) compared the spectra of amethyst, "burnt amethyst," which had been changed to yellow by heat treatment, and citrine.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ The violet pigment of amethyst is, then, probably a ferric compound, which is decomposed by heat to the yellow citrine pigment.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ Upon being heated, darker amethysts become identical in color and absorption spectrum with citrine, which is thought to be colored by a ferric compound.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

.Carnelian is widely heat-treated to deepen its color.^ On the contrary, the violet color is very rarely produced except when the color of pale or heated amethyst is deepened by radiation.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ The color of heat-decolorized smoky quartz is restored by radiation, and the color of pale specimens may be deepened in that manner.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

.Due to natural quartz being so often twinned, much of the quartz used in industry is synthesized.^ These facts suggest that the pigmenting of natural smoky quartz is due to the radiation of colorless quartz by radioactive substances in the solutions from which it formed.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ The decolorization of smoky quartz by heat can be explained as being due to the oxidation of silicon atoms, causing them to revert to their original character as parts of the quartz lattice.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ Smoky quartz, and more especially amethyst, are often twinned, the boundaries between the individuals in the twinned crystals being generally sharp and quite regular.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

Large, flawless and untwinned crystals are produced in an autoclave via the hydrothermal process; emeralds are also synthesized in this fashion. While these are still commonly referred to as quartz, the correct term for this material is silicon dioxide.

Occurrence

.Quartz is an essential constituent of granite and other felsic igneous rocks.^ A few occurrences of amethyst and smoky quartz in calcareous rocks, sandstones, and quartzites, in which there was no known genetic connection with igneous rocks, have been reported.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ Only very pale varieties occur elsewhere than in acid igneous rocks, which are much more radioactive than other types of rocks.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ IN CAVITIES IN DEEP-SEATED IGNEOUS ROCKS, PRINCIPALLY PEGMATITES - Both amethyst and smoky quartz occur frequently in the deep-seated igneous rocks, especially in the drusy cavities of pegmatites.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

.It is very common in sedimentary rocks such as sandstone and shale and is also present in variable amounts as an accessory mineral in most carbonate rocks.^ Manganese and titanium cannot be the coloring agents, since they are present only in small amounts which do not vary with the depth of color.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ Such minerals as the carbonates, the sulfides, barite, and fluorite are common associates of amethyst in ore veins.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ It is significant that the amethyst from amygdules in basic igneous rocks is usually very dark, while that in pegmatites and related veins is most apt to be pale.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

It is also a common constituent of schist, gneiss, quartzite and other metamorphic rocks. Because of its resistance to weathering it is very common in stream sediments and in residual soils.
.Quartz occurs in hydrothermal veins as gangue along with ore minerals.^ Smoky quartz occurs most typically in the drusy cavities of pegmatites and the similar Alpine type of veins.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ IN HYDROTHERMAL VEINS CLOSELY ASSOCIATED WITH GRANITES AND PEGMATITES - These quartz veins were formed by the silica-bearing aqueous solutions which were the last differentiation products of acidic magmas.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ Such minerals as the carbonates, the sulfides, barite, and fluorite are common associates of amethyst in ore veins.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

Large crystals of quartz are found in pegmatites. .Well-formed crystals may reach several meters in length and weigh hundreds of kilograms.^ CRYSTAL FORM - Amethyst is nearly always well crystallized, and smoky quartz frequently so, in contrast to the universally massive form of rose quartz.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

.Naturally occurring quartz crystals of extremely high purity, necessary for the crucibles and other equipment used for growing silicon wafers in the semiconductor industry, are expensive and rare.^ Blanks were run with definite weights of rock crystal powder, using the same amount and concentration of acid as in the smoky quartz tests.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ However, naturally colorless quartz rarely becomes violet when radiated, but usually takes on a smoky brown coloration.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ A zonal coloring like that observed in naturally colored quartz crystals is sometimes produced by radiation.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

A major mining location for high purity quartz is the Spruce Pine Gem Mine in Spruce Pine, North Carolina.[12]

Related silica minerals

Tridymite and cristobalite are high-temperature polymorphs of SiO2 that occur in high-silica volcanic rocks. .Coesite is a denser polymorph of quartz found in some meteorite impact sites and in metamorphic rocks formed at pressures greater than those typical of the Earth's crust.^ It is shown that amethyst and smoky quartz were crystallized from hot aqueous solutions in cavities, under less pressure than normal for the depth at which they were formed, and in a temperature range of about 110-220 for smoky quartz, and 90-250 for amethyst.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ The amount of UO 3 indicated by these analyses is about fifty times greater than that ordinarily found in colorless quartz.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ It forms at 90 to 250 C., under lower pressure and higher temperature than is normal at the depth where crystallization takes place.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

.Stishovite is a yet denser and higher-pressure polymorph of quartz found in some meteorite impact sites.^ Some observations made during the present study verify Vanzetti's experiments on smoky quartz The scattering of light from quartz was found to be of three types: .
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ The amethyst crystal in question must undoubtedly have formed at a temperature and pressure falling at some point on the curve, but one quantity must be known if the other is to be found.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

.Lechatelierite is an amorphous silica glass SiO2 which is formed by lightning strikes in quartz sand.^ IN HYDROTHERMAL VEINS CLOSELY ASSOCIATED WITH GRANITES AND PEGMATITES - These quartz veins were formed by the silica-bearing aqueous solutions which were the last differentiation products of acidic magmas.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ With too great a concentration of silica the cryptocrystalline or poorly crystallized varieties of quartz are likely to be formed.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

History

.
Fatimid carved rock crystal (clear quartz) vase, c.
^ The decolorized smoky quartz and decolorized radiated rose quartz gave about the same amount of silica as the rock crystal blanks.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ Blanks were run with definite weights of rock crystal powder, using the same amount and concentration of acid as in the smoky quartz tests.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ The pleochroism of rock crystal which had been colored brown by radium radiations was found to be identical with that of natural smoky quartz.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

1000
Quartz crystal showing transparency
The word "quartz" comes from the German About this sound Quarz ,[13] which is of Slavic origin (Czech miners called it křemen). .Other sources attribute the word's origin to the Saxon word Querkluftertz, meaning cross-vein ore.^ Specimens Nos 19, 17a, and 17b differ from the others analyzed in being massive specimens from ore veins, which accounts for the relatively high MnO content.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

[14]
Quartz is the most common material identified as the mystical substance maban in Australian Aboriginal mythology. It is found regularly in passage tomb cemeteries in Europe in a burial context, such as Newgrange or Carrowmore in the Republic of Ireland. The Irish word for quartz is grian cloch, which means 'stone of the sun'.
.While jade has been since earliest times the most prized semi-precious stone for carving in East Asia and Pre-Columbian America, in Europe and the Middle East the different varieties of quartz were the most commonly used for the various types of jewelry and hardstone carving, including engraved gems and cameo gems, rock crystal vases, and extravagant vessels.^ The decolorized smoky quartz and decolorized radiated rose quartz gave about the same amount of silica as the rock crystal blanks.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ The localities and the depths of color of the various specimens of smoky quartz used in this investigation are given in Table I, below.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ Blanks were run with definite weights of rock crystal powder, using the same amount and concentration of acid as in the smoky quartz tests.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

.The tradition continued to produce objects that were very highly valued until the mid-19th century, when it largely fell from fashion except in jewelry.^ On the contrary, the violet color is very rarely produced except when the color of pale or heated amethyst is deepened by radiation.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

Cameo technique exploits the bands of color in onyx and other varieties.
.Roman naturalist Pliny the Elder believed quartz to be water ice, permanently frozen after great lengths of time.^ Given the necessarily great time element, such amounts of radium could well cause the color of smoky quartz.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

(The word "crystal" comes from the Greek word for purity.) He supported this idea by saying that quartz is found near glaciers in the Alps, but not on volcanic mountains, and that large quartz crystals were fashioned into spheres to cool the hands. .He also knew of the ability of quartz to split light into a spectrum.^ The light transmitted through smoky quartz is strongest in the red and steadily decreases to the violet end of the spectrum.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ Vanzetti (55) found that the maximum of absorption of light by smoky quartz is in the violet portion of the spectrum.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

This idea persisted until at least the 1600s.
In the 17th century, Nicolas Steno's study of quartz paved the way for modern crystallography. .He discovered that no matter how distorted a quartz crystal, the long prism faces always made a perfect 60° angle.^ CRYSTAL FORM - Amethyst is nearly always well crystallized, and smoky quartz frequently so, in contrast to the universally massive form of rose quartz.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ The almost black original color is completely discharged at 420, but at lower temperatures, no matter how long the heating is continued, an increasingly greater residue of the color remains.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

.Charles B. Sawyer invented the commercial quartz crystal manufacturing process in Cleveland, Ohio, United States.^ Koenigsberger (24) states that in the central Alps the intensity of color of the smoky quartz crystals depends upon the altitude of the occurrence.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

This initiated the transition from mined and cut quartz for electrical appliances to manufactured quartz.
Quartz's piezoelectric properties were discovered by Jacques and Pierre Curie in 1880. The quartz oscillator or resonator was first developed by Walter Guyton Cady in 1921.[15] George Washington Pierce designed and patented quartz crystal oscillators in 1923.[16] Warren Marrison created the first quartz oscillator clock based on the work of Cady and Pierce in 1927.[17]

Piezoelectricity

.Quartz crystals have piezoelectric properties; they develop an electric potential upon the application of mechanical stress.^ As shown by the description of the physical properties in section II, the application of these criteria to smoky quartz and amethyst prove unquestionably that they were formed below 575, as the alpha modification of quartz.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ JUDD, JOHN W. Additional notes on the lamellar structure of quartz crystals and the methods by which it is developed.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ Koenigsberger (24) states that in the central Alps the intensity of color of the smoky quartz crystals depends upon the altitude of the occurrence.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

.An early use of this property of quartz crystals was in phonograph pickups.^ Blanks were run with definite weights of rock crystal powder, using the same amount and concentration of acid as in the smoky quartz tests.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

One of the most common piezoelectric uses of quartz today is as a crystal oscillator. The quartz clock is a familiar device using the mineral. The resonant frequency of a quartz crystal oscillator is changed by mechanically loading it, and this principle is used for very accurate measurements of very small mass changes in the quartz crystal microbalance and in thin-film thickness monitors.

See also

Notes

  1. ^ a b c Deer, W. A., R. A. Howie and J. Zussman, An Introduction to the Rock Forming Minerals, Logman, 1966, pp. 340–355 ISBN 0-582-44210-9
  2. ^ Handbook of Mineralogy. Quartz
  3. ^ Mindat. Quartz
  4. ^ Webmineral. Quartz
  5. ^ Hurlbut, Cornelius S.; Klein, Cornelis (1985). Manual of Mineralogy (20 ed.). ISBN 0-471-80580-7. 
  6. ^ http://www.etymonline.com/index.php?term=quartz etymonline.com
  7. ^ Heaney, Peter J. (1994). "Structure and Chemistry of the low-pressure silica polymorphs". Reviews in Mineralogy and Geochemistry 29 (1): 1–40. http://rimg.geoscienceworld.org/cgi/content/abstract/29/1/1. 
  8. ^ http://www.mindat.org/min-1054.html
  9. ^ Mindat. Rose Quartz
  10. ^ Colored Varieties of Quartz, Caltech
  11. ^ Milky quartz at Mineral Galleries
  12. ^ Sue Nelson (2 August 2009). "Silicon Valley's secret recipe". BBC News. http://news.bbc.co.uk/2/hi/technology/8178580.stm. 
  13. ^ German Loan Words in English
  14. ^ Mineral Atlas, Queensland University of Technology
  15. ^ "The Quartz Watch – Walter Guyton Cady". The Lemelson Center, National Museum of American History. Smithsonian Institution. http://invention.smithsonian.org/centerpieces/quartz/inventors/cady.html. 
  16. ^ "The Quartz Watch – George Washington Pierce". The Lemelson Center, National Museum of American History. Smithsonian Institution. http://invention.smithsonian.org/centerpieces/quartz/inventors/pierce.html. 
  17. ^ "The Quartz Watch – Warren Marrison". The Lemelson Center, National Museum of American History. Smithsonian Institution. http://invention.smithsonian.org/centerpieces/quartz/inventors/clock.html. 

References

External links


1911 encyclopedia

Up to date as of January 14, 2010

From LoveToKnow 1911

.QUARTZ, a widely distributed mineral species, consisting of silicon dioxide, or silica (S102).^ Quartz is a silicon dioxide.
  • Quartz, Golden | Great South Gems & Minerals | Rocks, Fossils and Crystals 12 January 2010 1:01 UTC www.greatsouth.net [Source type: General]
  • Quartz Crystals Points | Great South Gems & Minerals | Rocks, Fossils and Crystals 25 September 2009 7:53 UTC www.greatsouth.net [Source type: General]

^ Quartz Quartz (Silica/Silicon Dioxide, SiO2) is the most common mineral on the earth's surface.
  • Quartz/Engineered Stone Countertops - Keidel Bath, Kitchen, Plumbing, Cabinetry, Appliances - Cincinnati, OH 12 January 2010 1:01 UTC www.keidel.com [Source type: FILTERED WITH BAYES]

^ ARTICLE from the Encyclopædia Britannica mineral widely distributed mineral of many varieties that consists primarily of silica, or silicon dioxide (SiO 2 ).
  • quartz (mineral) -- Britannica Online Encyclopedia 12 January 2010 1:01 UTC www.britannica.com [Source type: Reference]

.It is the commonest of minerals, and is met with in a great variety of forms and with very diverse modes of occurrence.^ The mineral quartz forms in a variety of geologic environments.
  • Geology of quartz crystals: Rockhounding Arkansas 12 January 2010 1:01 UTC www.rockhoundingar.com [Source type: FILTERED WITH BAYES]

^ Quartz occurs in a great number of varieties that differ in form and color.
  • Bitterroot Gem & Mineral 12 January 2010 1:01 UTC bitterrootgms.org [Source type: FILTERED WITH BAYES]

^ Quartz also occurs in crystalline and microcrystalline massive forms of great variety.
  • QUARTZ Factsheet and Information Page 12 January 2010 1:01 UTC www.mineralminers.com [Source type: Reference]

.The various forms of silica have attracted attention from the earliest times, and the water-clear crystallized variety was known to the Greeks as KOo-raXXos (clear ice), being supposed by them to have been formed from water by the intense cold of the Alps; hence the name "crystal," or more commonly rock-crystal, applied to this variety.^ Quartz that forms from the crystallization of magmatic rocks crystallizes from a melt that is rich in silica and water.
  • Geology of quartz crystals: Rockhounding Arkansas 12 January 2010 1:01 UTC www.rockhoundingar.com [Source type: FILTERED WITH BAYES]

^ Rock crystal The transparent, colourless variety of quartz is still known as rock crystal.
  • Quartz - english 12 January 2010 1:01 UTC www.gemstone.org [Source type: General]

^ Rock Crystal: Rock Crystal is the name for clear, colorless Quartz.
  • Bitterroot Gem & Mineral 12 January 2010 1:01 UTC bitterrootgms.org [Source type: FILTERED WITH BAYES]

The name quartz is an old German word of uncertain origin: it was used by G. Agricola in 1529.
.Quartz is a mineral which is put to many uses.^ Quartz is an important mineral with numerous uses.
  • The mineral quartz 12 January 2010 1:01 UTC www.minerals.net [Source type: FILTERED WITH BAYES]

^ There are many reasons why Quartz is important in industry today, such as in the sand used in the manufacture of glass, or the rock crystals used in electronic equipment, i.e.

^ This quartz gravel was the source for many years of quartz for optical and electronic applications as well as being used to manufacture the seed blanks for growing synthetic quartz crystals.
  • Geology of quartz crystals: Rockhounding Arkansas 12 January 2010 1:01 UTC www.rockhoundingar.com [Source type: FILTERED WITH BAYES]

.Several of the varieties are cut into gems and ornaments, balance weights, pivot supports for delicate instruments, agate mortars, &c.; or used for engraving, for instance, cameos and the elaborately carved crystal vases of ancient and medieval times.^ Quartz - rock crystal , the most common gem variety of quartz crystal, is, like all quartz, formed from the two most abundant elements in the earth's crust: silicon and oxygen.
  • Quartz and Gemstones - SHG Resources 12 January 2010 1:01 UTC www.shgresources.com [Source type: FILTERED WITH BAYES]

^ Usually, it is cut into large stones above 5 carats weight, and this makes it a very affordable large gem ideal for jewelry.You are going to fall in love with soft sparkle of our lemon quartz jewelry.
  • http://www.semiprecious.com/LemonQuartz.cfm 12 January 2010 1:01 UTC www.semiprecious.com [Source type: General]

^ Polished rock crystal spheres or crystal balls were used as a means of divination or scrying in medieval times.
  • QUARTZ Factsheet and Information Page 12 January 2010 1:01 UTC www.mineralminers.com [Source type: Reference]

.Clear transparent rock-crystal is used for optical purposes and spectacle lenses.^ Transparent Rock Crystal is used in the study of optics.
  • The mineral quartz 12 January 2010 1:01 UTC www.minerals.net [Source type: FILTERED WITH BAYES]

^ Transparent "rock crystal" quartz.
  • Quartz Mineral | Photos, Uses, Properties, Pictures - GEOLOGY.COM 12 January 2010 1:01 UTC geology.com [Source type: Reference]

^ A clear, "rock crystal" variety of quartz.
  • Quartz Mineral | Photos, Uses, Properties, Pictures - GEOLOGY.COM 12 January 2010 1:01 UTC geology.com [Source type: Reference]

.Fused quartz has recently been used for the construction of lenses and laboratory vessels, or it may be drawn out into the finest elastic fibres and used for suspending mirrors, &c., in physical apparatus.^ There are even some rarer "twinned" Quartz crystals where two mirror-image crystals grow out of or into each other, and thus the crystal will alternately be left and right handed.

^ Actually, they've been made by the pharmaceutical industry for decades if not longer for use in laboratories because of the purity and non-transfer nature of quartz.

^ The dissociation is greatly enhanced when the heating of fused quartz is carried out in reducing conditions.
  • Quartz Properties 12 January 2010 1:01 UTC www.quartz.com [Source type: Reference]
  • Momentive Performance Materials 12 January 2010 1:01 UTC www.gequartz.com [Source type: Reference]

For striking fire, flint is used even to the present day. .Buhrstone, a cellular variety of chalcedonic quartz from the Tertiary strata of the Paris basin, is largely used for millstones.^ Fine quality lemon quartz gemstones are faceted and set onto a large variety of stylish silver settings to become a part of this appealing silver lemon quartz bracelet collection.
  • http://www.semiprecious.com/LemonQuartz.cfm 12 January 2010 1:01 UTC www.semiprecious.com [Source type: General]

^ Many rock collectors covet the large crystal (called macrocrystalline) varieties of Quartz, but Quartz comes in many different shapes, sizes and styles.

^ Crushed quartz is used as an abrasive in sandpaper, silica sand is employed in sandblasting, and sandstone is still used whole to make whetstones, millstones, and grindstones.
  • quartz (mineral) -- Britannica Online Encyclopedia 12 January 2010 1:01 UTC www.britannica.com [Source type: Reference]

.Quartz is a valuable grinding and polishing material, and is used for making sandpaper and scouring-soap.^ Quartz is an ideal material to use as an oscillator.
  • Quartz watches 12 January 2010 1:01 UTC www.bidtheewell.com [Source type: FILTERED WITH BAYES]

^ High Q-value of quartz crystal materials.
  • Quartz Crystal, Quartz Crystal Manufacturers & Suppliers 25 September 2009 7:53 UTC www.alibaba.com [Source type: General]

^ To prepare Quartz for use in a therapeutic necklace, the surface of the spheres must be roughened through a polishing process that makes the spheres appear white, or "frosted."
  • Quartz - Attracting Life Force - Information and Online Ordering 12 January 2010 1:01 UTC www.gemisphere.com [Source type: General]

.It is also largely used in the manufacture of glass and porcelain, "silver sand" being a pure quartz sand.^ Quartz is used today in the manufacture of abrasives, concrete, cements, porcelain, paints and glass.
  • QUARTZ Factsheet and Information Page 12 January 2010 1:01 UTC www.mineralminers.com [Source type: Reference]

^ Quartz sand is used as a filler in the manufacture of rubber, paint and putty.
  • Quartz Mineral | Photos, Uses, Properties, Pictures - GEOLOGY.COM 12 January 2010 1:01 UTC geology.com [Source type: Reference]

^ In fact, the finer crystals are pure enough to manufacture synthetic quartz components in computers.
  • Quartz and Gemstones - SHG Resources 12 January 2010 1:01 UTC www.shgresources.com [Source type: FILTERED WITH BAYES]

.Quartz crystallizes in the trapezohedral-hemihedral class of the rhombohedral division of the hexagonal system.^ It occurs in crystals of the hexagonal system, commonly having the form of a six-sided prism terminating in a six-sided pyramid; the crystals are often distorted and twins are common.
  • quartz Facts, information, pictures | Encyclopedia.com articles about quartz 12 January 2010 1:01 UTC www.encyclopedia.com [Source type: Academic]

^ Quartz Chemical composition: SiO 2 Class: tectosilicate Crystal system: Hexagonal-R; 32 (trigonal-trapezohedral) Crystal habit: Macroscopic Quartz crystals commonly occur as horizontally striated hexagonal prisms terminated by a combination of positive and negative rhombohedrons forming six sided pyramids.
  • QUARTZ Factsheet and Information Page 12 January 2010 1:01 UTC www.mineralminers.com [Source type: Reference]

^ Crystallographically, quartz crystal belongs to the trigonal system and point group symmetry 32.
  • Quartz crystal device 25 September 2009 7:53 UTC www.qiaj.jp [Source type: Reference]

.Crystals of this class possess neither planes nor centre of symmetry, but only axes of symmetry: perpendicular to the principal triad axis there are three uniterminal dyad axes of symmetry.^ Other Characteristics: Striations on prism faces running up the length of the crystal (perpendicular to C axis), piezoelectric, and refraction index is 1.55.

^ Phase plate (wave plate) Light falls on a quartz crystal plate in a direction perpendicular to the optical axis travels in the quartz crystal plate in the same direction.
  • Quartz crystal device 25 September 2009 7:53 UTC www.qiaj.jp [Source type: Reference]

^ The curves marked w and a were obtained by passing plane polarized light through the section in a direction perpendicular to the c axis.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

.Usually, however, this lower degree of symmetry is not indicated by the faces developed on the crystals.^ Their faces and radiance usually indicates where they have been!

^ Prism faces and/or rhombohedral terminations may be lacking, poorly developed or predominant resulting in diverse possible crystal habits.
  • QUARTZ Factsheet and Information Page 12 January 2010 1:01 UTC www.mineralminers.com [Source type: Reference]

.The majority of crystals of quartz are bounded only by the faces of a hexagonal prism m{2111 and a hexagonal bipyramid (fig.^ Some "C Face" quartz crystals have been found.
  • Quartz 12 January 2010 1:01 UTC www.uwex.edu [Source type: Academic]

^ Other Characteristics: Striations on prism faces running up the length of the crystal (perpendicular to C axis), piezoelectric, and refraction index is 1.55.

^ It occurs in crystals of the hexagonal system, commonly having the form of a six-sided prism terminating in a six-sided pyramid; the crystals are often distorted and twins are common.
  • quartz Facts, information, pictures | Encyclopedia.com articles about quartz 12 January 2010 1:01 UTC www.encyclopedia.com [Source type: Academic]

I), though sometimes the prism is absent (fig. 2). Frequently the faces are of different sizes (fig. 3): mis-shapen crystals FIG. I. FIG. 2. FIG. 3.
are common and sometimes very puzzling, but they can always be orientated by the aid of the very characteristic striations, on the prism faces, which serve also to distinguish quartz from other minerals of similar appearance. These striations (fig. .3) are horizontal in direction, being parallel to the edges of intersection between the prism and pyramid faces, and are due to the frequent oscillatory combination of these faces.^ It is semi-transparent with multiple stepped pyramidal terminations and multiple parallel prismatic faces.
  • Quartz Crystals (natural quartz crystals) 25 September 2009 7:53 UTC www.mineralminers.com [Source type: General]

^ It has natural dissolution features on its surfaces with some multiple stepped pyramidal terminations and some multiple parallel prismatic faces.
  • Quartz Crystals (natural quartz crystals) 25 September 2009 7:53 UTC www.mineralminers.com [Source type: General]

^ Its upper surface is covered with natural stepped pyramidal terminations and multiple parallel prismatic faces.
  • Quartz Crystals (natural quartz crystals) 25 September 2009 7:53 UTC www.mineralminers.com [Source type: General]

.The apparent hexagonal bipyramid is really a combination of two rhombohedra, the direct rhombohedron r{ loo} and the inverse rhombohedron z{221{.^ Crystal Habit: Widely variable, but most commonly as hexagonal prisms terminated by two rhombohedrons which create a six-sided pyramid.

.The faces of these two rhombohedra exhibit differences in surface characters, those of r being usually brighter in lustre than those of z; further, the former often predominate in size (figs.^ Sandstone-hosted deposits usually contain less quartz volumetrically than shale-hosted deposits, but often yield a higher percentage of clear crystals in cavities or pockets.
  • Geology of quartz crystals: Rockhounding Arkansas 12 January 2010 1:01 UTC www.rockhoundingar.com [Source type: FILTERED WITH BAYES]

^ Arkansas quartz crystal point in fine silver free form wrap pendant Note these crystals are good sized and heavier than the Brazilian crystal points we make they are also brighter than the subdued Brazilian points.
  • quartz crystal jewelry - new age point crystal pendants - Arkansas crystal point pendants - Brazilian crystal point pendants 25 September 2009 7:53 UTC www.wehug.com [Source type: General]

^ We have these natural rose quartz bead necklaces available in two bead diameter sizes: 4.5mm and 8mm.
  • Rose Quartz SPECTACULAR DECORATOR and COLLECTOR ITEMS at MINERALMINERS.COM 11 October 2009 10:51 UTC www.mineralminers.com [Source type: General]

4 and 5), and the latter may sometimes be completely absent. .When both the prism and the rhombohedron z are absent, the crystals resemble cubes in appearance, since the angles between the faces of the rhombohedron are 85° 46'. The additional faces s and x (figs.^ Other Characteristics: Striations on prism faces running up the length of the crystal (perpendicular to C axis), piezoelectric, and refraction index is 1.55.

^ Trigonal trapezoheldral faces can occur in upper right or left of alternating prism faces which identify right or left-handed crystals respectively.

^ Prism faces and/or rhombohedral terminations may be lacking, poorly developed or predominant resulting in diverse possible crystal habits.
  • QUARTZ Factsheet and Information Page 12 January 2010 1:01 UTC www.mineralminers.com [Source type: Reference]

.4 and 5), which indicate the true degree of symmetry of quartz, are of comparatively rare occurrence except on crystals from certain localities.^ Quartz crystals exhibit a property called the piezoelectric effect, that is, they produce an electric voltage when subjected to pressure along certain directions of the crystal.
  • http://www.semiprecious.com/Quartz.cfm 12 January 2010 1:01 UTC www.semiprecious.com [Source type: General]

^ Only rarely does Quartz outwardly shows its true symmetry by small Trapezohedral x- faces which modify the corners of the prism m-faces where the prism faces intersect the pyramid faces.
  • Bitterroot Gem & Mineral 12 January 2010 1:01 UTC bitterrootgms.org [Source type: FILTERED WITH BAYES]

^ Transparent rose quartz is very rare and is usually so pale that it does not show very much color except in large sizes.
  • Quartz Healing and Metaphysical Properties of Gemstones from Shimmerlings Jewelry 12 January 2010 1:01 UTC www.shimmerlings.com [Source type: FILTERED WITH BAYES]

.The six small faces s{412} situated on alternate corners at each end of the crystal, are called the "rhomb" faces, because of their shape; if extended they would give a trigonal bipyramid.^ Quartz crystals exhibit a property called the piezoelectric effect, that is, they produce an electric voltage when subjected to pressure along certain directions of the crystal.
  • http://www.semiprecious.com/Quartz.cfm 12 January 2010 1:01 UTC www.semiprecious.com [Source type: General]

^ Only rarely does Quartz outwardly shows its true symmetry by small Trapezohedral x- faces which modify the corners of the prism m-faces where the prism faces intersect the pyramid faces.
  • Bitterroot Gem & Mineral 12 January 2010 1:01 UTC bitterrootgms.org [Source type: FILTERED WITH BAYES]

^ Many rock collectors covet the large crystal (called macrocrystalline) varieties of Quartz, but Quartz comes in many different shapes, sizes and styles.

The "trapezohedral," or "plagihedral," faces x {41a} belong to a trigonal trapezohedron. The two crystals shown in figs. .4 and 5 are FIG. 4. FIG. 5. enantiomorphous, i.e. they are non-superposable, one being the mirror reflection of the other: they are left-handed and right-handed crystals respectively.^ This gives the crystal the ability to be either a left or right handed crystal.

^ There are even some rarer "twinned" Quartz crystals where two mirror-image crystals grow out of or into each other, and thus the crystal will alternately be left and right handed.

^ On a micron scale, Quartz is made up of a lattice of silica Tetrahedral (SiO4) arranged in right hand or left hand helixes.
  • Bitterroot Gem & Mineral 12 January 2010 1:01 UTC bitterrootgms.org [Source type: FILTERED WITH BAYES]

.The faces s are striated parallel to their edge of intersection with r; this serves to distinguish r and z, and thus, in the absence of x faces, to distinguish leftor right-handed crystals.^ Other Characteristics: Striations on prism faces running up the length of the crystal (perpendicular to C axis), piezoelectric, and refraction index is 1.55.

^ There are even some rarer "twinned" Quartz crystals where two mirror-image crystals grow out of or into each other, and thus the crystal will alternately be left and right handed.

^ Trigonal trapezoheldral faces can occur in upper right or left of alternating prism faces which identify right or left-handed crystals respectively.

.Numerous other faces have been observed on crystals of quartz, but they are of rare occurrence.^ Some "C Face" quartz crystals have been found.
  • Quartz 12 January 2010 1:01 UTC www.uwex.edu [Source type: Academic]

^ Quartz crystals exhibit a property called the piezoelectric effect, that is, they produce an electric voltage when subjected to pressure along certain directions of the crystal.
  • http://www.semiprecious.com/Quartz.cfm 12 January 2010 1:01 UTC www.semiprecious.com [Source type: General]

^ Only rarely does Quartz outwardly shows its true symmetry by small Trapezohedral x- faces which modify the corners of the prism m-faces where the prism faces intersect the pyramid faces.
  • Bitterroot Gem & Mineral 12 January 2010 1:01 UTC bitterrootgms.org [Source type: FILTERED WITH BAYES]

.The basal plane, so common on calcite and many other rhombohedral minerals, is of the greatest rarity in quartz, and when present only appears as a small rough face formed by the corrosion of the crystal.^ Some "C Face" quartz crystals have been found.
  • Quartz 12 January 2010 1:01 UTC www.uwex.edu [Source type: Academic]

^ Quartz crystals can also contain other minerals "frozen" within, as in Rutilated Quartz.
  • Quartz Healing and Metaphysical Properties of Gemstones from Shimmerlings Jewelry 12 January 2010 1:01 UTC www.shimmerlings.com [Source type: FILTERED WITH BAYES]

^ Twinning : Quartz has only 3 types of common twins; 1.
  • Bitterroot Gem & Mineral 12 January 2010 1:01 UTC bitterrootgms.org [Source type: FILTERED WITH BAYES]

.Faces of prisms other than m are also small and of exceptional occurrence.^ Only rarely does Quartz outwardly shows its true symmetry by small Trapezohedral x- faces which modify the corners of the prism m-faces where the prism faces intersect the pyramid faces.
  • Bitterroot Gem & Mineral 12 January 2010 1:01 UTC bitterrootgms.org [Source type: FILTERED WITH BAYES]

.Twinned crystals of quartz are extremely common, but are complex in character and can only be deciphered when the faces s and x are present, which is not often the case.^ Some "C Face" quartz crystals have been found.
  • Quartz 12 January 2010 1:01 UTC www.uwex.edu [Source type: Academic]

^ Twinning : Quartz has only 3 types of common twins; 1.
  • Bitterroot Gem & Mineral 12 January 2010 1:01 UTC bitterrootgms.org [Source type: FILTERED WITH BAYES]

^ Quartz is the most common mineral found on the face of the earth and occurs in all environments and all rock types - sedimentary, metamorphic or igneous.

.Usually they are interpenetration twins with the principal axis as twin-axis; the prism planes of the two individuals coincide, and the faces r and z also fall into the same plane.^ Their faces and radiance usually indicates where they have been!

^ Other Characteristics: Striations on prism faces running up the length of the crystal (perpendicular to C axis), piezoelectric, and refraction index is 1.55.

^ The explanations which have been advanced to account for the production of color by the radiation of a mineral fall into two main classes: .
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

.Such twins may therefore be mistaken for simple crystals unless they are attentively studied; but the twinning is often made evident by the presence of irregularly bounded areas of the duller z faces coinciding with the brighter r faces.^ Prism faces and/or rhombohedral terminations may be lacking, poorly developed or predominant resulting in diverse possible crystal habits.
  • QUARTZ Factsheet and Information Page 12 January 2010 1:01 UTC www.mineralminers.com [Source type: Reference]

^ Smoky quartz, and more especially amethyst, are often twinned, the boundaries between the individuals in the twinned crystals being generally sharp and quite regular.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ Regardless of the name given to these fascinating crystals, they are beautiful and often exotic in appearance.

.In a rarer type of twinning, in which the twin-plane is 1521) (a plane truncating the edge between r and z), the two individuals are united in juxtaposition with their principal axis nearly at right angles (84° 33').^ Smoky quartz, and more especially amethyst, are often twinned, the boundaries between the individuals in the twinned crystals being generally sharp and quite regular.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ Brazil twins are optical twins : Light waves that pass through an untwined right or left Quartz Crystal along its c axis change the orientation of their oscillation plane in either left or right direction.
  • Bitterroot Gem & Mineral 12 January 2010 1:01 UTC bitterrootgms.org [Source type: FILTERED WITH BAYES]

^ Twinning: Dauphine twin with c the twin axis, Brazil twin with {1120} the twin plane, Japanese twin is rare with {1122} the twin plane.
  • QUARTZ Factsheet and Information Page 12 January 2010 1:01 UTC www.mineralminers.com [Source type: Reference]

.A few magnificent specimens of rock-crystal twinned according to this law have been found at La Gardette in Isere, and in Japan they are somewhat abundant.^ Quartz - rock crystal , the most common gem variety of quartz crystal, is, like all quartz, formed from the two most abundant elements in the earth's crust: silicon and oxygen.
  • Quartz and Gemstones - SHG Resources 12 January 2010 1:01 UTC www.shgresources.com [Source type: FILTERED WITH BAYES]

^ Cluster of clear Quartz crystals (" Rock Crystal ") from Arkansas in which the crystals are about six times as long as they are thick.
  • All varieties of quartz and chalcedony 12 January 2010 1:01 UTC www.minerals.net [Source type: General]

^ Natural Quartz Crystal (rock crystal) Mineral Specimens .
  • Quartz Crystals (natural quartz crystals) 25 September 2009 7:53 UTC www.mineralminers.com [Source type: General]

.The pyro-electric characters of quartz are closely connected with its peculiar type of symmetry and especially with the three uniterminal dyad axes.^ In general, the electrical insulating properties of clear fused quartz are superior to those of the opaque or translucent types.
  • Quartz Properties 12 January 2010 1:01 UTC www.quartz.com [Source type: Reference]

^ Some observations made during the present study verify Vanzetti's experiments on smoky quartz The scattering of light from quartz was found to be of three types: .
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

.A crystal becomes positively and negatively electrified in alternate prism edges when its temperature changes.^ To accomplish this, though, use your crystals to increase and amplify the positive until there is nowhere for the negative to go but elsewhere.

^ Trigonal trapezoheldral faces can occur in upper right or left of alternating prism faces which identify right or left-handed crystals respectively.

^ Trigonal tapezohedral faces can occur in the upper right or left of alternating prism faces identifying right or left handed crystals, respectively.
  • QUARTZ Factsheet and Information Page 12 January 2010 1:01 UTC www.mineralminers.com [Source type: Reference]

.A similar distribution of electric charges is produced when a crystal is subjected to pressure; quartz being thus also piezo-electric.^ EGOROFF, N. Dichroism produced by radium in colorless quartz, and a thermo-electric effect observed on the colored striae.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ A zonal coloring like that observed in naturally colored quartz crystals is sometimes produced by radiation.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ While there is little else to be found in myth and lore concerning Smoky Quartz, the crystal of course is linked closely to Clear Quartz (Rock Crystal) and thus it can be said to also share in that wealth of myth and lore.

.Etched figures, both natural and artificial (in the latter case produced by the action of hydrofluoric acid), on the faces of the crystals are in accordance with the symmetry, and may serve to distinguish leftand righthanded crystals.^ This pear shape gem of natural quartz crystal faces up completely clean even under very close inspection.
  • Natural Quartz Crystal Pyramids, Vogels, Lingams, Carvings, Hearts, Massage Wands and Skulls 25 September 2009 7:53 UTC www.mineralminers.com [Source type: General]

^ The surface of this semi-transparent crystal are in good overall condition with some minor abrasions, and it is naturally terminated at both ends.
  • Quartz Crystals (natural quartz crystals) 25 September 2009 7:53 UTC www.mineralminers.com [Source type: General]

^ Both artificial and natural smoky quartz are decolorized at moderate temperatures.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

.In its optical characters, quartz is also of interest, since it is one of the two minerals (cinnabar being the other) which are circularly polarizing.^ Such quartz often includes traces of other minerals picked up by water flowing underground.
  • Quartz and Gemstones - SHG Resources 12 January 2010 1:01 UTC www.shgresources.com [Source type: FILTERED WITH BAYES]

^ Quartz crystal can also be used to amplify the powers of other crystals and minerals in your healing practices.
  • Quartz Crystal (Clusters, Tibetan, Spirit, Elestial) - Earth Healing Crystals 25 September 2009 7:53 UTC www.earthhealingcrystals.com [Source type: General]
  • Quartz Crystal (Clusters, Tibetan, Spirit, Elestial) - Earth Healing Crystals 25 September 2009 7:53 UTC www.earthhealingcrystals.com [Source type: General]

^ Quartz is a chemical compound consisting of one part silicon and two parts oxygen.
  • Quartz Mineral | Photos, Uses, Properties, Pictures - GEOLOGY.COM 12 January 2010 1:01 UTC geology.com [Source type: Reference]

.This phenomenon is connected with the symmetry of the crystals, and is also shown by the crystals of certain other substances in which there are neither planes nor centre of symmetry.^ The beauty and power of the vibrations emitted from the quartz crystal music allows the mind to take a “holy-day” and connect us with our powerful energy centres - in the body and above the body.

^ There are many planes and veils within this magnificent crystal ball , and there also are some nice rainbow reflections inside it.
  • Natural Quartz Crystal Pyramids, Vogels, Lingams, Carvings, Hearts, Massage Wands and Skulls 25 September 2009 7:53 UTC www.mineralminers.com [Source type: General]

.A ray of plane-polarized light traversing a right-handed crystal of quartz in the direction of the triad axis has its plane of polarization rotated to the right, while a left-handed crystal rotates it to the left.^ Brazil twins are optical twins : Light waves that pass through an untwined right or left Quartz Crystal along its c axis change the orientation of their oscillation plane in either left or right direction.
  • Bitterroot Gem & Mineral 12 January 2010 1:01 UTC bitterrootgms.org [Source type: FILTERED WITH BAYES]

^ The light was failing quickly, so we opted to portage rather than risk injury if the right side was as shallow as the left.

^ A light filled transformational pendant that could also be used by a healer to direct healing energy where needed through the crystal point.

A section I mm. thick, cut perpendicular to the principal axis of a quartz crystal, rotates the plane of yellow (D) light through 22°, and of blue (G) light through 43°. .Such a section when examined in the polariscope shows an interference figure with a coloured centre, there being no black cross inside the innermost ring (this is not shown in very thin sections).^ Very clean and sharp smokey quartz crystal, no damage but there is a contact from a feldspar crystal on the backside.
  • Natural quartz specimens from Chris Tucker Minerals. 12 January 2010 1:01 UTC www.christuckerminerals.com [Source type: FILTERED WITH BAYES]

^ In both cases the original section scattered light strongly while the decolorized section showed little or no scattering.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ The most common being Actinolite and Tremolite (the others, such as Glaucophane, Hornblende, and Riebeckite, being brown, blue or black.
  • Crystal Vaults::Quartz Crystals - Their Identification and Meanings 12 January 2010 1:01 UTC www.crystalvaults.com [Source type: FILTERED WITH BAYES]

.Superimposed sections of rightand left-handed quartz, as may sometimes be present in sections of twinned crystals, exhibit Airy's spirals in the polariscope.^ Quartz crystals exhibit a property called the piezoelectric effect, that is, they produce an electric voltage when subjected to pressure along certain directions of the crystal.
  • http://www.semiprecious.com/Quartz.cfm 12 January 2010 1:01 UTC www.semiprecious.com [Source type: General]

^ There are even some rarer "twinned" Quartz crystals where two mirror-image crystals grow out of or into each other, and thus the crystal will alternately be left and right handed.

^ Unusual Quartz Crystals or Formations: This section covers those aspects of quartz morphology that are not covered in the descriptions of crystal forms, habits, and twinning, and also covers those related to the overall appearance of crystals or crystal aggregates.
  • Bitterroot Gem & Mineral 12 January 2010 1:01 UTC bitterrootgms.org [Source type: FILTERED WITH BAYES]

.The indices of refraction of quartz for yellow (D) light are co = I.5442 and e = I. 5533; the optic sign is therefore positive.^ Quartz crystal music holds the vibration of white light which ultimately refracts into the rainbow and acts directly on our chakras when played.

^ Silica glass (also called fused quartz ) is used in optics to transmit ultraviolet light .
  • quartz (mineral) -- Britannica Online Encyclopedia 12 January 2010 1:01 UTC www.britannica.com [Source type: Reference]

^ Item : Light Golden-Yellow Elestial Quartz Sphere, 5.5 inch .
  • Natural Quartz Crystal Pyramids, Vogels, Lingams, Carvings, Hearts, Massage Wands and Skulls 25 September 2009 7:53 UTC www.mineralminers.com [Source type: General]

Quartz has a hardness of 7 (being chosen as No. .7 on Mohs' scale), and it cannot be scratched with a knife; its specific gravity is 2.65. There is no distinct cleavage; though an imperfect cleavage may sometimes be developed parallel to the faces of the rhombohedron r by plunging a heated crystal into cold water.^ In fine lamellae parallel to the rhombohedron faces.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ Specific Gravity: 2.65, but may be less in cryptocrystalline form.

^ Cryptocrystalline quartz shows no cleavage, although parting may occur along layers and splintery fracture can develope parallel to microfibrous orientation.
  • QUARTZ Factsheet and Information Page 12 January 2010 1:01 UTC www.mineralminers.com [Source type: Reference]

.The glassy conchoidal fracture is a characteristic feature of the crystallized mineral.^ Quartz crystals are recognized by their crystal habit, striations, hardness, glassy luster, conchoidal fracture, occurance and general lack of cleavage.
  • QUARTZ Factsheet and Information Page 12 January 2010 1:01 UTC www.mineralminers.com [Source type: Reference]

^ Fracture: conchoidal Streak: white Electrical properties: rock crystal quartz is strongly piezoelectric and pyroelectric Return to the Index of Quartz Information Topics .
  • QUARTZ Factsheet and Information Page 12 January 2010 1:01 UTC www.mineralminers.com [Source type: Reference]

.A peculiar rippled or "thumb-marked" fracture is sometimes to be seen, especially in amethyst, and is due to repeated intergrowths of rightand left-handed material.^ Many, such as Amethyst and Rose Quartz , are universally accepted and used, others are sometimes used, and yet others are hardly ever seen or made up.
  • All varieties of quartz and chalcedony 12 January 2010 1:01 UTC www.minerals.net [Source type: General]

.The mineral is a non-conductor of electricity; it is unattacked by acids with the exception of hydrofluoric acid, and is only slightly dissolved by solutions of caustic alkalis.^ The fused quartz should then be placed in a 7% (maximum) solution of ammonium bifluoride for no more than ten minutes, or a 10 vol % (maximum) solution of hydrofluoric acid for no more than five minutes.
  • Quartz Properties 12 January 2010 1:01 UTC www.quartz.com [Source type: Reference]

It is infusible before the gas blowpipe, but in the oxyhydrogen flame fuses to a clear colourless glass, which has a hardness of 5 and specific gravity 2.2.
.Many peculiarities of the growth of crystals are well illustrated by the mineral quartz.^ Many of the quartz crystal show exhibit hopper like growth.
  • Natural quartz specimens from Chris Tucker Minerals. 12 January 2010 1:01 UTC www.christuckerminerals.com [Source type: FILTERED WITH BAYES]

^ Quartz crystal with a phantom growth .
  • All varieties of quartz and chalcedony 12 January 2010 1:01 UTC www.minerals.net [Source type: General]

^ Quartz crystal with a scepter growth.
  • All varieties of quartz and chalcedony 12 January 2010 1:01 UTC www.minerals.net [Source type: General]

.Thus in "ghost quartz," in which one crystal is seen inside another, the stages of growth are marked out by thin layers of enclosed material.^ High Q-value of quartz crystal materials.
  • Quartz Crystal, Quartz Crystal Manufacturers & Suppliers 25 September 2009 7:53 UTC www.alibaba.com [Source type: General]

^ There are even some rarer "twinned" Quartz crystals where two mirror-image crystals grow out of or into each other, and thus the crystal will alternately be left and right handed.

^ Many of the quartz crystal show exhibit hopper like growth.
  • Natural quartz specimens from Chris Tucker Minerals. 12 January 2010 1:01 UTC www.christuckerminerals.com [Source type: FILTERED WITH BAYES]

.In "capped quartz" these layers are thicker, and the successive shells of the crystal may be easily separated.^ Although colorless quartz is relatively common, large flawless specimens are not, which is why most crystal balls these days are made of glass, not quartz.
  • Quartz Healing and Metaphysical Properties of Gemstones from Shimmerlings Jewelry 12 January 2010 1:01 UTC www.shimmerlings.com [Source type: FILTERED WITH BAYES]

^ Cryptocrystalline quartz shows no cleavage, although parting may occur along layers and splintery fracture can develope parallel to microfibrous orientation.
  • QUARTZ Factsheet and Information Page 12 January 2010 1:01 UTC www.mineralminers.com [Source type: Reference]

^ These crystals are also known as angel quartz crystals due to the inclusions sometimes having a wispy effect resembling wings.
  • Crystal Vaults::Quartz Crystals - Their Identification and Meanings 12 January 2010 1:01 UTC www.crystalvaults.com [Source type: FILTERED WITH BAYES]

."Sceptre quartz," in which a short thick crystal is mounted on the end of a long slender prism, indicates a change in the conditions of growth.^ The largest quartz crystal is 2.5cm long.
  • Natural quartz specimens from Chris Tucker Minerals. 12 January 2010 1:01 UTC www.christuckerminerals.com [Source type: FILTERED WITH BAYES]

^ Quartz crystal with a phantom growth .
  • All varieties of quartz and chalcedony 12 January 2010 1:01 UTC www.minerals.net [Source type: General]

^ Quartz crystal with a scepter growth.
  • All varieties of quartz and chalcedony 12 January 2010 1:01 UTC www.minerals.net [Source type: General]

Crystals with a helical twist are not uncommon. .Enclosures of other minerals (rutile, chlorite, haematite, gothite, actinolite, asbestos and many others) are extremely frequent in crystals of quartz.^ Quartz crystals can also contain other minerals "frozen" within, as in Rutilated Quartz.
  • Quartz Healing and Metaphysical Properties of Gemstones from Shimmerlings Jewelry 12 January 2010 1:01 UTC www.shimmerlings.com [Source type: FILTERED WITH BAYES]

^ Because of this property, quartz crystal has important applications in the electronics industry for controlling the frequency of radio waves.
  • http://www.semiprecious.com/Quartz.cfm 12 January 2010 1:01 UTC www.semiprecious.com [Source type: General]

^ There are many reasons why Quartz is important in industry today, such as in the sand used in the manufacture of glass, or the rock crystals used in electronic equipment, i.e.

.Cavities, either rounded or with the same shape ("negative crystals") as the surrounding crystal, are also common; they are often of minute size and present in vast numbers.^ Negative crystal cavities are illustrated by b and d .
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ Crystals are often used in numbers of 5, 7, 11, 13 or 21 for circles and rituals.
  • Quartz Healing and Metaphysical Properties of Gemstones from Shimmerlings Jewelry 12 January 2010 1:01 UTC www.shimmerlings.com [Source type: FILTERED WITH BAYES]

^ Natural Healers use Smoky Quartz crystals to remove negative energy from within the body and surrounding the person.
  • Smoky Quartz Jewelry Earrings Necklace Bracelet Silver 12 January 2010 1:01 UTC www.luckygemstones.com [Source type: General]

.Usually these cavities contain a liquid (water, a saline solution, carbon dioxide or petroleum) and a movable bubble of gas.^ INCLUSIONS CONSISTING OF WATER ALONE, OR OF AN AQUEOUS SOLUTION, BUT WITH NO FREE CARBON DIOXIDE - Such cavities contain small contraction bubbles, due to the cooling of the liquid from its temperature when enclosed in the growing quartz crystal The temperature at which the bubble just disappeared was determined.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ These are crystals that contain pockets of liquid, trapped inside the crystal during its formation.
  • Bitterroot Gem & Mineral 12 January 2010 1:01 UTC bitterrootgms.org [Source type: FILTERED WITH BAYES]

^ HAWES, G. W. On liquid carbon dioxide in smoky quartz.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

.The presence of these enclosed impurities impairs the transparency of crystals.^ These quartz crystal beads have beautiful gem-grade transparency.
  • Natural Quartz Crystal Pyramids, Vogels, Lingams, Carvings, Hearts, Massage Wands and Skulls 25 September 2009 7:53 UTC www.mineralminers.com [Source type: General]

^ The largest of these lightly included crystals have good transparency, and they are in good overall condition with some minor abrasions.
  • Quartz Crystals (natural quartz crystals) 25 September 2009 7:53 UTC www.mineralminers.com [Source type: General]

^ These natural quartz crystal beads have superior transparency ranging from faintly included to internally flawless, and they have not been heated or treated in any way!
  • Natural Quartz Crystal Pyramids, Vogels, Lingams, Carvings, Hearts, Massage Wands and Skulls 25 September 2009 7:53 UTC www.mineralminers.com [Source type: General]

.Crystals of quartz are usually attached at one end to their rocky matrix, but sometimes, especially when embedded in a soft matrix of clay, gypsum or salt, they may be bounded on all sides by crystal faces (fig.^ Some "C Face" quartz crystals have been found.
  • Quartz 12 January 2010 1:01 UTC www.uwex.edu [Source type: Academic]

^ Quartz crystals exhibit a property called the piezoelectric effect, that is, they produce an electric voltage when subjected to pressure along certain directions of the crystal.
  • http://www.semiprecious.com/Quartz.cfm 12 January 2010 1:01 UTC www.semiprecious.com [Source type: General]

^ Quartz is the most common mineral found on the face of the earth and occurs in all environments and all rock types - sedimentary, metamorphic or igneous.

I). .In size they vary between wide limits, from minute sparkling points encrusting rock surfaces and often so thickly clustered together as to produce a drusy effect, to large single crystals measuring a yard in length and diameter and weighing half a ton.^ Large Quartz Crystals (rock crystal) Large Quartz Clusters and Rare Quality Quartz Crystal Items .
  • Natural Quartz Crystal Pyramids, Vogels, Lingams, Carvings, Hearts, Massage Wands and Skulls 25 September 2009 7:53 UTC www.mineralminers.com [Source type: General]

^ Quartz crystals exhibit a property called the piezoelectric effect, that is, they produce an electric voltage when subjected to pressure along certain directions of the crystal.
  • http://www.semiprecious.com/Quartz.cfm 12 January 2010 1:01 UTC www.semiprecious.com [Source type: General]

^ Crystal Size: The largest single Quartz Crystal which has been substantiated was found at Mancho Felipe, near Itapore, Goiaz, Brazil in 1962; and was 20 feet long, 5 feet across a prism face, and was estimated to have weighed over 44 tons.
  • Bitterroot Gem & Mineral 12 January 2010 1:01 UTC bitterrootgms.org [Source type: FILTERED WITH BAYES]

Missing image
Quartz-1.jpg
.The characters as given above apply more particularly to crystals of quartz, but in the various massive and compact varieties the material may be quite different in general appearance.^ High Q-value of quartz crystal materials.
  • Quartz Crystal, Quartz Crystal Manufacturers & Suppliers 25 September 2009 7:53 UTC www.alibaba.com [Source type: General]

^ Secondary veins, the main filling of which is quartz—partly compact, partly comby and banded with drusy crystals—were seen at all the principal openings on Mine Hill.

^ Unusual Quartz Crystals or Formations: This section covers those aspects of quartz morphology that are not covered in the descriptions of crystal forms, habits, and twinning, and also covers those related to the overall appearance of crystals or crystal aggregates.
  • Bitterroot Gem & Mineral 12 January 2010 1:01 UTC bitterrootgms.org [Source type: FILTERED WITH BAYES]

.Thus in the microcrystalline chalcedony the lustre is waxy, the fracture fibrous to even, and the external form botryoidal or stalactitic flint and chert are compact and have a splintery fracture: jasper is a compact variety intermixed with much iron oxide and clay and has a dull and even fracture.^ History of Quartz: The names and uses for the varieties of Quartz (flint, jasper, chalcedony, and rock-crystal) have changed over time since its first use by man, perhaps more than one million years ago.
  • Bitterroot Gem & Mineral 12 January 2010 1:01 UTC bitterrootgms.org [Source type: FILTERED WITH BAYES]

.Further, these varieties may be of almost any colour, whereas transparent crystals have only a limited range of colour, being either colourless (rock-crystal), violet (amethyst), brown (smoky quartz) or yellow (citrine).^ Color smoky quartz and amethyst .
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ Quartz can have mineral inclusions that are fluorescent, and these will show through the transparent Rock-Crystal.
  • Bitterroot Gem & Mineral 12 January 2010 1:01 UTC bitterrootgms.org [Source type: FILTERED WITH BAYES]

^ Amethyst, too, may show these characters.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

.Quartz occurs as a primary and essential constituent of igneous rocks of acidic composition such as granite, quartz-porphyry and rhyolite, being embedded in these either as irregularly shaped masses or as porphyritic crystals.^ It is an essential constituent of igneous rocks such as granite, rhyolite, and pegmatite, which contain an excess of silica.
  • http://www.semiprecious.com/Quartz.cfm 12 January 2010 1:01 UTC www.semiprecious.com [Source type: General]

^ These effects were first discovered in crystals such as Quartz and Tourmaline.

^ Quartz is the most common mineral found on the face of the earth and occurs in all environments and all rock types - sedimentary, metamorphic or igneous.

.In pegmatite (graphic granite) and granophyre it often forms a regular intergrowth with felspar.^ IN HYDROTHERMAL VEINS CLOSELY ASSOCIATED WITH GRANITES AND PEGMATITES - These quartz veins were formed by the silica-bearing aqueous solutions which were the last differentiation products of acidic magmas.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

.It is also a common constituent, as irregular grains, in many gneisses and crystalline schists, a quartz-schist being composed largely of quartz.^ Although colorless quartz is relatively common, large flawless specimens are not, which is why most crystal balls these days are made of glass, not quartz.
  • Quartz Healing and Metaphysical Properties of Gemstones from Shimmerlings Jewelry 12 January 2010 1:01 UTC www.shimmerlings.com [Source type: FILTERED WITH BAYES]

^ Rose Quartz is found in many places in the world, and usually forms in large masses.
  • Hearts - Rose Quartz Hearts - Healing Crystals 11 October 2009 10:51 UTC www.healingcrystals.com [Source type: General]

^ Many rock collectors covet the large crystal (called macrocrystalline) varieties of Quartz, but Quartz comes in many different shapes, sizes and styles.

.By the weathering of silicates, silica passes into solution and quartz is deposited as a secondary product in the cavities of basic igneous rocks, and in fact in the crevices and along the joints of rocks of almost all kinds.^ It is generally found in amygdaloidal cavities of basic igneous rocks, or cavities in pegmatites.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ Secondary veins, the main filling of which is quartz—partly compact, partly comby and banded with drusy crystals—were seen at all the principal openings on Mine Hill.

^ Quartz is the most common mineral found on the face of the earth and occurs in all environments and all rock types - sedimentary, metamorphic or igneous.

.Extensive veins of quartz are especially frequent in schistose rocks.^ POLK COUNTY: Quartz crystals up to 15 cm long occur in quartz veins in the Dresser Trap Rock Quarry, Sec.
  • Quartz 12 January 2010 1:01 UTC www.uwex.edu [Source type: Academic]

^ IN CAVITIES IN DEEP-SEATED IGNEOUS ROCKS, PRINCIPALLY PEGMATITES - Both amethyst and smoky quartz occur frequently in the deep-seated igneous rocks, especially in the drusy cavities of pegmatites.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ Radiation of almost any specimen of quartz, such as rock crystal, or rose quartz, or frequently even amethyst itself, brings about the brown coloration.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

.Vein-quartz, often of economic importance as a matrix of gold, may, however, in some cases have been of igneous origin.^ White Quartz streaked with Gold veins.
  • All varieties of quartz and chalcedony 12 January 2010 1:01 UTC www.minerals.net [Source type: General]

^ Amethyst has often been noted in the silver veins which Lindgren 5 describes as "deposits formed near the surface by ascending thermal waters and in genetic connection with igneous rocks."
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ Smoky quartz is found in the veins in adularia gneiss, biotite gneiss, granites, and acid like rocks, but the quartz in the veins traversing schists of sedimentary origin and basic igneous rocks is almost always colorless.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

.In mineral veins and lodes crystallized quartz is usually the most abundant gangue mineral; the crystals are often arranged perpendicular to the walls of the lode, giving rise to a "comby" structure.^ Quartz is the most abundant mineral.
  • Quartz 12 January 2010 1:01 UTC www.uwex.edu [Source type: Academic]

^ Secondary veins, the main filling of which is quartz—partly compact, partly comby and banded with drusy crystals—were seen at all the principal openings on Mine Hill.

^ Although colorless quartz is relatively common, large flawless specimens are not, which is why most crystal balls these days are made of glass, not quartz.
  • Quartz Healing and Metaphysical Properties of Gemstones from Shimmerlings Jewelry 12 January 2010 1:01 UTC www.shimmerlings.com [Source type: FILTERED WITH BAYES]

.In limestones of various kinds it occurs as nodules and bands of chert and flint, being in this case of organic origin.^ Quartz also occurs as chert, banded chert and drusy crystals in the Sweeney Quarry, NW SW sec.
  • Quartz 12 January 2010 1:01 UTC www.uwex.edu [Source type: Academic]

.Quartz being a mineral very resistant to weathering agencies, it forms the bulk of sands and sandstones; and when the sand grains are cemented together by a later deposit of secondary quartz a rock known as quartzite results.^ Quartz is the most common mineral found on the face of the earth and occurs in all environments and all rock types - sedimentary, metamorphic or igneous.

^ They have no visible prism faces and hence are much more like calcite forms than any other crystals of quartz known to the author.

^ There are many reasons why Quartz is important in industry today, such as in the sand used in the manufacture of glass, or the rock crystals used in electronic equipment, i.e.

.Pseudomorphous quartz, i.e. quartz replacing other minerals, is of frequent occurrence, and as a petrifying material replacing organic remains it is often met with.^ In the Ontario occurrence the near presence of active material outside the quartz could easily have colored it.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ Quartz crystal can also be used to amplify the powers of other crystals and minerals in your healing practices.
  • Quartz Crystal (Clusters, Tibetan, Spirit, Elestial) - Earth Healing Crystals 25 September 2009 7:53 UTC www.earthhealingcrystals.com [Source type: General]
  • Quartz Crystal (Clusters, Tibetan, Spirit, Elestial) - Earth Healing Crystals 25 September 2009 7:53 UTC www.earthhealingcrystals.com [Source type: General]

^ Quartz is colorless if pure, but may assume any color due to inclusions of other minerals or built-in trace elements.
  • Bitterroot Gem & Mineral 12 January 2010 1:01 UTC bitterrootgms.org [Source type: FILTERED WITH BAYES]

.As a deposit from hot springs, quartz is much less common than opal.^ They have no visible prism faces and hence are much more like calcite forms than any other crystals of quartz known to the author.

^ In amethyst the dichroism is less uniform than in smoky quartz, due to the usual zoning of the colors.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

^ It is shown that amethyst and smoky quartz were crystallized from hot aqueous solutions in cavities, under less pressure than normal for the depth at which they were formed, and in a temperature range of about 110-220 for smoky quartz, and 90-250 for amethyst.
  • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

.Crystals of quartz may be readily prepared artificially by a number of methods; for example, by heating glass or gelatinous silica with water under pressure.^ Quartz crystals exhibit a property called the piezoelectric effect, that is, they produce an electric voltage when subjected to pressure along certain directions of the crystal.
  • http://www.semiprecious.com/Quartz.cfm 12 January 2010 1:01 UTC www.semiprecious.com [Source type: General]

^ And even though this may be a youth watch, it still carries Game Time's trademark quality with quartz accuracy, water resistance to 3 ATM (99 ft.
  • Quartz Watches at bizrate - Price Comparison and Consumer Reviews 12 January 2010 1:01 UTC www.bizrate.com [Source type: General]

^ There are many reasons why Quartz is important in industry today, such as in the sand used in the manufacture of glass, or the rock crystals used in electronic equipment, i.e.

.For particulars respecting the special characters, modes of occurrence and localities of the more important varieties of quartz, reference may be made to the following articles: AGATE, AMETHYST, AVENTURINE, BLOODSTONE, CAIRNGORM, CARNELIAN, CAT'S-EYE, CHALCEDONY, CHRYSOPRASE, FLINT,HELIOTROPE,JASPER, MOCHASTONE, ONYX, ROCK-CRYSTAL, SARD, SARDONYX.^ Natural Quartz Crystal Rough (rock crystal) .
  • Natural Quartz Crystal Pyramids, Vogels, Lingams, Carvings, Hearts, Massage Wands and Skulls 25 September 2009 7:53 UTC www.mineralminers.com [Source type: General]

^ This term may also refer to Blue Rock Crystal .
  • All varieties of quartz and chalcedony 12 January 2010 1:01 UTC www.minerals.net [Source type: General]

^ Natural Quartz Crystal (rock crystal) Gemstones .
  • Quartz Crystals (natural quartz crystals) 25 September 2009 7:53 UTC www.mineralminers.com [Source type: General]

For other forms of silica see OPAL and TRIDYMITE. (L. J. S.)


Wiktionary

Up to date as of January 14, 2010
(Redirected to quartz article)

Definition from Wiktionary, a free dictionary

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Contents

English

Etymology

German Quarz from Middle High German twarc, probably from a West Slavic language (cf. Polish twardy (hard), Russian твёрдый (hard)), from Old Church Slavonic тврьдъ (firm), from Proto-Slavic *tvьrdъ.

Pronunciation

Noun

Singular
quartz
Plural
countable and uncountable; plural quartzes
quartz (countable and uncountable; plural quartzes)
  1. (mineralogy) The most abundant mineral on the earth's surface, of chemical composition silicon dioxide, SiO2. .It occurs in a variety of forms, both crystalline and amorphous.^ These varieties of quartz were generally formed after the colorless or white quartz of the pegmatites in which they occur, and after the chalcedony and agate of basic rocks.
    • Color smoky quartz and amethyst 12 January 2010 1:01 UTC www.minsocam.org [Source type: Academic]

    Found in every environment.

Derived terms

Translations

See also

See rock, granite, pegmatite

Simple English

File:Quartz
Quartz crystal

[[File:|thumb|240px|right|Quartz]] Quartz is a very common type of mineral. You may hear other names when it has colors or looks different. Agate, Amethyst, Rose quartz are some names for quartz. It is a semi-precious gemstone. Quartz is a component used to make quartz clocks. Sand often has a lot of small quartz bits. This mineral contains silica. Quartz has a mineral hardness of 8. (mohs scale).

The word "quartz" comes from the German word "quarz". It also came from "twark", which came from Slavic (cf. Czech tvrdy ("hard"), Polish twardy ("hard"), Russian твёрдый ("hard")), from Old Church Slavonic тврьдъ ("firm"), and from Proto-Slavic *tvьrdъ. [1]

Quartz can be useful in many ways, for example TV and clock screens, jewelry and glass. Quartz crystals can often be found in mountains and high-altitude areas.

References

  1. http://www.etymonline.com/index.php?term=quartz etymonline.com


Citable sentences

Up to date as of December 23, 2010

Here are sentences from other pages on Quartz, which are similar to those in the above article.








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