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Emerald

Emerald crystal from Muzo, Colombia
General
Category Beryl variety
Chemical formula Beryllium aluminium silicate with chromium, Be3Al2(SiO3)6::Cr
Identification
Color Green
Crystal habit Hexagonal Crystals
Crystal system Hexagonal
Cleavage Poor Basal Cleavage (Seldom Visible)
Fracture Conchoidal
Mohs scale hardness 7.5–8.0
Luster Vitreous
Streak White
Specific gravity 2.70–2.78
Refractive index 1.576–1.582
Pleochroism Distinct, Blue-Green/Yellow-Green

Emeralds are a variety of the mineral beryl (Be3Al2(SiO3)6,) colored green by trace amounts of chromium and sometimes vanadium.[1] Beryl has a hardness of 7.5–8 on the 10 point Mohs scale of mineral hardness.[1] Most emeralds are highly included, so their toughness (resistance to breakage) is classified as generally poor. The word "emerald" comes (via Middle English: Emeraude, imported from Old French: Ésmeraude, and Medieval Latin: Esmaraldus) from Latin smaragdus, via Greek smaragdos – σμάραγδος ("green gem"), its original source being a Semitic word izmargad (אזמרגד), meaning "emerald" or "green".[2]

Contents

Etymology

The name "Emerald" is derived (via Middle English: Emeraude and Old French: Esmeraude), from Vulgar Latin: Esmaralda/Esmaraldus, a variant of Latin Smaragdus, which originated in Greek: σμάραγδος (smaragdos; "green gem"), its original source being a Semitic word izmargad (אזמרגד) meaning "emerald" or "green".[2]. The name could also be related to the Semitic word baraq (בָּרָק ;البُراق‎; "lightning" or "shine") (c.f. Hebrew: ברקת bareqeth and Arabic: برق barq "lightning"). Its the same source for the Persian (زمرّد zomorrod), Turkish (zümrüt), Sanskrit मरग्दम् maragdam and Russian (изумруд; izumrúd) names . [3]

Properties determining value

Cut emeralds

Emeralds, like all colored gemstones, are graded using four basic parameters, the four Cs of Connoisseurship; Color, Cut, Clarity and Crystal. The last C, crystal is simply used as a synonym that begins with C for transparency or what gemologists call diaphaneity. Prior to the 20th Century jewelers used the term water as in "a gem of the finest water"[4] to express the combination of two qualities, color and crystal. Normally, in the grading of colored gemstones, color is by far the most important criterion. However, in the grading of emerald, crystal is considered a close second. Both are necessary conditions. A fine emerald must possess not only a pure verdant green hue as described below, but also a high degree of transparency to be considered a top gem.[5]

Color

Scientifically speaking, color is divided into three components: hue, saturation and tone. Yellow and blue, the hues found adjacent to green on the spectral color wheel, are the normal secondary hues found in emerald. Emeralds occur in hues ranging from yellow-green to blue-green. The primary hue must, of course, be green. Only gems that are medium to dark in tone are considered emerald. Light toned gems are known by the species name, green beryl. In addition, the hue must be bright (vivid). Gray is the normal saturation modifier or mask found in emerald. A grayish green hue is a dull green.

Clarity

Emerald tends to have numerous inclusions and surface breaking fissures. Unlike diamond, where the loupe standard, i.e. 10X magnification, is used to grade clarity, emerald is graded by eye. Thus, if an emerald has no visible inclusions to the eye (assuming normal visual acuity) it is considered flawless. Stones that lack surface breaking fissures are extremely rare and therefore almost all emeralds are treated, "oiled", to enhance the apparent clarity. Eye-clean stones of a vivid primary green hue (as described above) with no more than 15% of any secondary hue or combination (either blue or yellow) of a medium-dark tone command the highest prices.[5] This relative crystal non-uniformity makes emeralds more likely than other gemstones to be cut into cabochons, rather than faceted shapes.

Treatments

Most emeralds are oiled as part of the post lapidary process, in order to improve their clarity. Cedar oil, having a similar refractive index, is often used in this generally accepted practice. Other liquids, including synthetic oils and polymers with refractive indexes close to that of emerald such as Opticon are also used. The U.S. Federal Trade Commission requires the disclosure of this treatment when a treated emerald is sold.[6] The use of oil is traditional and largely accepted by the gem trade. Other treatments, for example the use of green-tinted oil, are not acceptable in the trade. The laboratory community has recently standardized the language for grading the clarity of emeralds. Gems are graded on a four step scale; none, minor, moderate and highly enhanced. Note that these categories reflect levels of enhancement not clarity. A gem graded none on the enhancement scale may still exhibit visible inclusions. Laboratories tend to apply these criteria differently. Some gem labs consider the mere presence of oil or polymers to constitute enhancement. Others may ignore traces of oil if the presence of the material does not materially improve the look of the gemstone.

Given that the vast majority of all emeralds are treated as described above, and the fact that two stones that appear to be similar in quality may actually be quite far apart in treatment level, a consumer considering a purchase of an expensive emerald is well advised to insist upon a treatment report from a reputable gemological laboratory. All other factors being equal, a high quality emerald with an enhancement level graded moderate should cost 40–50% less than an identical stone graded none.

Emerald localities

Spanish emerald and gold pendant exhibited at Victoria and Albert Museum.

Emeralds in antiquity were mined by the Egyptians and in Austria.[7][8]

A rare type of emerald known as a trapiche emerald is occasionally found in the mines of Colombia. A trapiche emerald exhibits a "star" pattern; it has raylike spokes of dark carbon impurities that give the emerald a six-pointed radial pattern.[citation needed] Emeralds come from three main emerald mining areas in Colombia: Muzo, Coscuez, and Chivor.[citation needed] Emeralds are also found in other countries, such as Afghanistan, Australia, Austria, Brazil, Bulgaria, Canada, China, Egypt, Ethiopia, France, Germany, India, Italy, Kazakhstan, Madagascar, Mozambique, Namibia, Nigeria, Norway, Pakistan, Russia, Somalia, South Africa, Spain, Switzerland, Tanzania, United States, Zambia and Zimbabwe.[9] In the US, emeralds have been found in Connecticut, Montana, Nevada, North Carolina and South Carolina.[9] In 1998 emeralds were discovered in the Yukon.[citation needed]

Synthetic emerald

Emerald showing its hexagonal structure

Emerald is a rare and valuable gemstone and, as such, it has provided the incentive for developing synthetic emeralds. Both hydrothermal and flux-growth synthetics have been produced, and a method has been developed for producing an emerald overgrowth on colorless beryl. The first commercially successful emerald synthesis process was that of Carroll Chatham. Because Chatham's emeralds do not have any water and contain traces of vanadate, molybdenum and vanadium, a lithium vanadate flux process is probably involved. The other large producer of flux emeralds was Pierre Gilson Sr., which has been on the market since 1964. Gilson's emeralds are usually grown on natural colorless beryl seeds which become coated on both sides. Growth occurs at the rate of 1 mm per month, a typical seven-month growth run producing emerald crystals of 7 mm of thickness.[10] Gilson sold his production laboratory to a Japanese firm in the 1980s, but production has ceased since, so did Chatham's, after the San Francisco earthquake in 1989.[citation needed]

Hydrothermal synthetic emeralds have been attributed to IG Farben, Nacken, Tairus, and others, but the first satisfactory commercial product was that of Johann Lechleitner of Innsbruck, Austria, which appeared on the market in the 1960s. These stones were initially sold under the names "Emerita" and "Symeralds", and they were grown as a thin layer of emerald on top of natural colorless beryl stones. Although not much is known about the original process, it is assumed that Leichleitner emeralds were grown in acid conditions.[citation needed] Later, from 1965 to 1970, the Linde Division of Union Carbide produced completely synthetic emeralds by hydrothermal synthesis. According to their patents (US3,567,642 and US3,567,643), acidic conditions are essential to prevent the chromium (which is used as the colorant) from precipitating. Also, it is important that the silicon-containing nutrient be kept away from the other ingredients to prevent nucleation and confine growth to the seed crystals. Growth occurs by a diffusion-reaction process, assisted by convection. The largest producer of hydrothermal emeralds today is Tairus in Russia. They have succeeded to synthesize emeralds that have similar chemical composition as emeralds in alkaline deposits in Colombia, hence they are called “Colombian Created Emeralds” or “Tairus Created Emeralds.”[citation needed]

Luminescence in ultraviolet light is considered a supplementary test when making a natural vs. synthetic determination, as many, but not all, natural emeralds are inert to ultraviolet light. Many synthetics are also UV inert.[11]

Synthetic emeralds are often referred to as "created", as their chemical and gemological composition is the same as their natural counterparts. The U.S. Federal Trade Commission (FTC) has very strict regulations as to what can and what cannot be called "synthetic" stone. The FTC says: "§ 23.23(c) It is unfair or deceptive to use the word "laboratory-grown," "laboratory-created," "[manufacturer name]-created," or "synthetic" with the name of any natural stone to describe any industry product unless such industry product has essentially the same optical, physical, and chemical properties as the stone named."[12]

Wispy veil-like inclusions are common in flux-grown synthetic emeralds.

Emerald in different cultures, and emerald lore

The Gachala Emerald is one of the largest gem emeralds in the world, at 858 carats (172 g). This stone was found in 1967 at La Vega de San Juan mine in Gachalá, Colombia. It is housed at the National Museum of Natural History of the Smithsonian Institution in Washington, D.C.

Emerald is regarded as the traditional birthstone for May, as well as the traditional gemstone for the astrological signs of Taurus, Cancer and sometimes Gemini. One of the more quaint anecdotes on emeralds was by the 16th-century historian Brantome, who referred to the many impressive emeralds the Spanish under Cortez had brought back to Europe from Latin America. On one of Cortez's most notable emeralds he had the text engraved Inter Natos Mulierum non sur-rexit mayor (Among them borne of woman there hath not arisen a greater Man. XI, 11) which referred to John the Baptist. Brantome considered engraving such a beautiful and simple product of nature sacrilegious and considered this act the cause for Cortez's loss of an extremely precious pearl (to which he dedicated a work A beautiful and incomparable pearl) and even for the death of King Charles IX of France who died soon after.[13]

In some cultures, the emerald is the traditional gift for the 55th wedding anniversary. It is also used as a 20th and 35th wedding anniversary stone.

The Authorized King James Version of the Bible, in Exodus 28:18 and 39:11, lists "emerald" as one of the precious stones in the breastplate of the high priest of the Jews; but modern consensus is that this is probably a mistranslation. (See Hoshen.)

Ireland is often referred to, especially in America, as the "Emerald Isle".

In L. Frank Baum's The Wonderful Wizard of Oz, the city where the wizard rules is made of emerald, thus being called Emerald City. The sixth book in the series is named after it.

Notable emeralds
Emerald Origin
Gachala Emerald Colombia
Chalk Emerald
Bahia Emerald Brazil

See also

Gallery

Notes

  1. ^ a b Hurlbut, Cornelius S. Jr, & Kammerling, Robert C., 1991, Gemology, p. 203, John Wiley & Sons, New York
  2. ^ a b Fernie M.D., W.T. (1906). Precious Stones for Curative Wear. John Wright. & Co.. 
  3. ^ Harper, Douglas. "emerald". Online Etymology Dictionary. http://www.etymonline.com/index.php?term=emerald. 
  4. ^ Crook & Ball eds., Tavernier, J. B. The Six Voyages, Vol II, pp.44, 58
  5. ^ a b Wise, R. W., Secrets Of The Gem Trade, The Connoisseur's Guide To Precious Gemstones, Brunswick House Press, 2001, pp.108
  6. ^ Guides for the Jewelry, Precious Metals, and Pewter Industries
  7. ^ Giuliani et al. (2000): “Oxygen Isotopes and Emerald Trade Routes Since Antiquity.” Gaston Giuliani, Marc Chaudisson, Henri-Jean Schubnel, Daniel-H. Piat, Claire Rollion-Bard, Christian France-Lanord, Didier Giard, Daniel de Narvaez, Benjamin Rondeau. Science, January 28, 2000, pp. 631–633.
  8. ^ Giuliani et al. (2000b): “La route des emeraudes anciennes.” Gaston Giuliani, Michèle Heuze, Marc Chaudisson. Pour la Science, November 2000, pp. 58–65.
  9. ^ a b http://www.mindat.org/min-1375.html Mindat with location data
  10. ^ Nassau, K., 1980, Gems Made By Man, Gemological Institute of America, ISBN 0873110161
  11. ^ Hurlbut, Cornelius S. Jr, & Kammerling, Robert C., 1991, Gemology, p. 81, John Wiley & Sons, New York
  12. ^ Guides for the Jewelry, Precious Metals, and Pewter Industries
  13. ^ Kunz, George Frederick (1915). Magic of Jewels and Charms. Lippincott Company.  p. 305

References

  • Cooper, J.C. (Ed.) (1992). Brewer's Myth and Legend. New York: Cassell Publishers Ltd. ISBN 0-304-34084-7.
  • Sinkankas, John (1994). Emerald & Other Beryls. Geoscience Press. ISBN 0-8019-7114-4
  • Hurlbut, Cornelius S.; Klein, Cornelis (1985). Manual of Mineralogy (20th ed.). New York: John Wiley and Sons. ISBN 0-471-80580-7
  • Weinstein, Michael (1958). The World of Jewel Stones. Sheriden House.
  • Nassau, Kurt (1980). Gems made by man. Gemological Institute of America. ISBN 0-87311-016-1
  • Ali, Saleem H. (2006). The Emerald City: Emerald mining in Brazil (+Gemstone mining in other countries) http://www.uvm.edu/envnr/gemecology/brazil.html
  • Wise, Richard W., Secrets of the Gem Trade, The Connoisseur's Guide To Precious Gemstones (2001), Brunswick House Press. ISBN 0-9728223-8-0. Website: [1]
  • Ball, V., & Crooke, W., Travels In India by Jean-Baptiste Tavernier, Oriental Reprint Corporation, New Delhi, India.

External links


1911 encyclopedia

Up to date as of January 14, 2010

From LoveToKnow 1911

EMERALD, a bright green variety of beryl, much valued as a gem-stone. The word comes indirectly from the Gr. if apay50s (Arabic zumurrud), but this seems to have been a name vaguely given to a number of stones having little in common except a green colour. Pliny's "smaragdus" undoubtedly included several distinct species. Much confusion has arisen with respect to the "emerald" of the Scriptures. The Hebrew word no phek, rendered emerald in the Authorized Version, probably meant the carbuncle: it is indeed translated avOpa in the Septuagint, and a marginal reading in the Revised Version gives carbuncle. On the other hand, the word baregath, rendered ap.fipaybos in the LXX., appears in the A.V. as carbuncle, with the alternative reading of emerald in the R.V. It may have referred to the true emerald, but Flinders Petrie suggests that it meant rock-crystal.

The properties of emerald are mostly the same as those described under Beryl. The crystals often show simply the hexagonal prism and basal plane. The prisms cleave, though imperfectly, at right angles to the geometrical axis; and hexagonal slices were formerly worn in the East. Compared with most gems, the emerald is rather soft, its hardness (7.5) being but slightly above that of quartz. The specific gravity is low, varying slightly in stones from different localities, but being for the Muzo emerald about 2.67. The refractive and dispersive powers are not high, so that the cut stones display little brilliancy or "fire." The emerald is dichroic, giving in the dichroscope a bluish-green and a yellowish-green image. The magnificent colour which gives extraordinary value to this gem, is probably due to chromium. F. Wohler found 0.186% of Cr 2 0 3 in the emerald of Muzo,- a proportion which, though small, is sufficient to impart an emerald-green colour to glass. The stone loses colour when strongly heated, and M. Lewy suggested that the colour was due to an organic pigment. Greville Williams showed that emeralds lost about 9% of their weight on fusion, the specific gravity being reduced to about 2.4.

The ancients appear to have obtained the emerald from Upper Egypt, where it is said to have been worked as early as 1650 B.C. It is known that Greek miners were at work in the time of Alexander the Great, and in later times the mines yielded their gems to Cleopatra. Remains of extensive workings were discovered in the northern Etbai by the French traveller, F. Cailliaud, in 1817, and the mines were re-opened for a short time under Mehemet Ali. "Cleopatra's Mines" are situated in Jebel Sikait and Jebel Zabara near the Red Sea coast east of Assuan. They were visited in 1891 by E. A. 'Toyer, and the Sikait workings were explored in 1900 by D. A. MacAlister and others. The Egyptian emeralds occur in mica-schist and talc-schist.

On the Spanish conquest of South America vast quantities of emeralds were taken from the Peruvians, but the exact locality which yielded the stones was never discovered. The only South American emeralds now known occur near Bogota, the capital of Colombia. The most famous mine is at Muzo, but workings are known also at Coscuez and Somondoco. The emerald occurs in nests of calcite in a black bituminous limestone containing ammonites of Lower Cretaceous age.. The mineral is associated with quartz, dolomite, pyrites, and the rare mineral called "parisite" - a fluo-carbonate of the cerium metals, occurring in brownish-yellow hexagonal crystals, and named after J. J. Paris, who worked the emeralds. It has been suggested that the Colombian emerald is not in its original matrix. The fine stones are called canutillos and the inferior ones morallion. In 1830 emeralds were accidentally discovered in the Ural Mountains. At the present time they are worked on the river Takovaya, about 60 m. N.E. of Ekaterinburg, where they occur in mica-schist, associated with aquamarine, alexandrite, phenacite, &c. Emerald is found also in mica-schist in the .Habachthal, in the Salzburg Alps, and in granite at Eidsvold in Norway. Emerald has been worked in a vein of pegmatite, piercing slaty rocks, near Emmaville, in New South Wales. The crystals occurred in association with topaz, fluorspar and cassiterite; but they were mostly of rather pale colour. In the United States, emerald has occasionally been found, and fine crystals have been obtained from the workings for hiddenite at Stonypoint, Alexander county, N.C.

Many virtues were formerly ascribed to the emerald. When worn, it was held to be a preservative against epilepsy, it cured dysentery, it assisted women in childbirth, it drove away evil spirits, and preserved the chastity of the wearer. Administered internally it was reputed to have great medicinal value. In consequence of its refreshing green colour it was naturally said to be good for the eyesight.

The stone known as "Oriental emerald" is a green corundum. Lithia emerald is the mineral called hiddenite; Uralian emerald is a name given to demantoid; Brazilian emerald is merely green tourmaline; evening emerald is the peridot; pyro-emerald is fluorspar which phosphoresces with a green glow when heated; and "mother of emerald" is generally a green quartz or perhaps in some cases a green felspar.

See [[Aquamarine, Beryl. (F. W. R. *) Emeric - David, Toussaint - Bernard]] (1755-1839), French archaeologist and writer on art, was born at Aix, in Provence, on the 10th of August 1755. He was destined for the legal profession, and having gone in 1775 to Paris to complete his legal education, he acquired there a taste for art which influenced his whole future career, and he went to Italy, where he continued his art studies. He soon returned, however, to his native village, and followed for some time the profession of an advocate; but in 1787 he succeeded his uncle Antoine David as printer to the parlement. He was elected mayor of Aix in 1791; and although he speedily resigned his office, he was in 1 793 threatened with arrest, and had for some time to adopt a vagrant life. When danger was past he returned to Aix, sold his printing business, and engaged in general commercial Ppursuits; but he was not long in renouncing these also, in order to devote himself exclusively to literature and art. From 1809 to 1814, under the Empire, he represented his department in the Lower House (Corps legislatif); in 1814 he voted for the downfall of Napoleon; in 1815 he retired into private life, and in 1816 he was elected a member of the Institute. He died in Paris on the 2nd of April 1839. Emeric-David was placed in 1825 on the commission appointed to continue L'Histoire litteraire de la France. His principal works are Recherches sur fart statuaire, considers chez les anciens et les modernes (Paris, 1805), a work which obtained the prize of the Institute; Suite d'etudes calquees et dessinees d'apres cinq tableaux de Raphael (Paris, 1818-1821), in 6 vols. fol.; Jupiter, ou recherches sur ce dieu, sur son culte, &c. (Paris, 1833) ,2 vols. 8vo, illustrated; and Vulcain (Paris,1837).


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Wiktionary

Up to date as of January 15, 2010

Definition from Wiktionary, a free dictionary

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See also emerald

English

Proper noun

Singular
Emerald

Plural
-

Emerald

  1. A town in Queensland, Australia.
  2. (rare) A female given name.
    • 1954 Theodore Sturgeon, The Golden Helix, in Leo Marguelis:Three Times Infinity, Fawcett Publications 1958, page 109:
      The child, a girl, was albino like April, and had exactly April's deep red eyes. Sol and Libra named her Emerald, a green name and a ground-term rather than a sky-term, as if in open expression of the slow spell worked on them all by Viridis.

Bible wiki

Up to date as of January 23, 2010

From BibleWiki


Heb. nophek (Ex 28:18; 39:11); i.e., the "glowing stone", probably the carbuncle, a precious stone in the breastplate of the high priest. It is mentioned (Rev 21:19) as one of the foundations of the New Jerusalem. The name given to this stone in the New Testament Greek is smaragdos, which means "live coal."

This entry includes text from Easton's Bible Dictionary, 1897.

what mentions this? (please help by turning references to this page into wiki links)

This article needs to be merged with EMERALD (Jewish Encyclopedia).

Simple English

An emerald is a mineral rock from the variety of beryl. It is the birthstone of someone whose birthday lands in the month of May. It is a green rock. The emerald is one of the most valuable gems, with ruby, opal, diamond, topaz, and sapphire and it is more valuable than diamonds.[needs proof]


Emerald of Panjsher

Etymology

The word emerald comes from Vulgar Latin. The word was Esmaralda/Esmaraldus, a different way of saying the Latin word Smaragdus, which came from the Greek, σμάραγδος (smaragdos; "green gem").[1][2] It first came from a Semitic word, izmargad (אזמרגד). This meant "emerald" or "green".[1] The name could also be related to the Semitic word baraq (בָּרָק ;البُراق‎; "lightning" or "shine") (c.f. Hebrew: ברקת bareqeth and Arabic: برق barq "lightning"). It is where the Persian (زمرّد zomorrod), Turkish (zümrüt), Sanskrit मरग्दम् maragdam and Russian (изумруд; izumrúd) words came from.[2]

Other pages

emerald is one of the most expensive stone in the world if we talk about panjsher emerald which is in afghanistan its the most famous stone all over the world

References

  1. 1.0 1.1 Fernie M.D., W.T. (1906). Precious Stones for Curative Wear. John Wright. & Co.. 
  2. 2.0 2.1 "Online Etymology Dictionary". etymonline.com. http://www.etymonline.com/index.php?search=emerald&searchmode=none. Retrieved 15 April 2010. 


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