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Baryte (Barite)
General
Category Sulfate mineral, Barite Group
Chemical formula BaSO4
Strunz classification 07.AD.35
Dana classification 28.03.01.01
Identification
Color Colorless, white, light shades of blue, yellow, grey, brown
Crystal habit Tabular parallel to base, fibrous, nodular to massive
Crystal system Orthorhombic Dipyramidal (2/m 2/m 2/m)
Cleavage Perfect cleavage parallel to base and prism faces: {001} Perfect, {210} Perfect, {010} Imperfect
Fracture Irregular/uneven
Tenacity Brittle
Mohs scale hardness 3-3.5
Luster Vitreous, pearly
Streak White
Diaphaneity transparent to opaque
Specific gravity 4.3-5
Density 4.48 g/cm3[1]
Optical properties biaxial positive
Refractive index nα = 1.634 - 1.637 nβ = 1.636 - 1.638 nγ = 1.646 - 1.648
Birefringence 0.012
Fusibility 4, yellowish green barium flame
Diagnostic features white color, high specific gravity, characteristic cleavage and crystals
Solubility low
References [2][3][4][5]

Baryte, or barite, (BaSO4) is a mineral consisting of barium sulfate.[2] The baryte group consists of baryte, celestine, anglesite and anhydrite. Baryte itself is generally white or colorless, and is the main source of barium. Baryte and celestine form a solid solution (Ba,Sr)SO4.[1]

Contents

Names and history

The unit cell of barite

The radiating form, sometimes referred to as Bologna Stone, attained some notoriety among alchemists for the phosphorescent specimens found in the 1600s near Bologna by Vincenzo Cascariolo.[6]

The name baryte is derived from the Greek word βαρύς (heavy). The American spelling barite[2] is used by USGS [7] and more often used in modern Scientific journals including those published by the Netherlands-based Elsevier journals. The International Mineralogical Association adopted "barite" as the official spelling when it formed in 1959[citation needed], but recommended adopting the older "baryte" spelling in 1978,[8] notably ignored by the Mineralogical Society of America. The American Petroleum Institute specification API 13/ISO 13500 which governs baryte for drilling purposes does not refer to any specific mineral, but rather a material that meets that specification, in practice this is usually the mineral baryte.

The term "primary baryte" refers to the first marketable product, which includes crude baryte (run of mine) and the products of simple beneficiation methods, such as washing, jigging, heavy media separation, tabling, flotation, and magnetic separation. Most crude baryte requires some upgrading to minimum purity or density. Baryte that is used as an aggregate in a "heavy" cement is crushed and screened to a uniform size. Most baryte is ground to a small, uniform size before it is used as a filler or extender, an addition to industrial products, or a weighting agent in petroleum well drilling mud.

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Other names

Baryte has gone by other names such as barytine,[8] barytite,[8] schwerspath,[8] barytes,[2] Heavy Spar,[2] or tiff.[3]

Mineral associations and locations

Baryte with Galena and Hematite from Poland

Baryte occurs in a large number of depositional environments, and is deposited through a large number of processes including biogenic, hydrothermal, and evaporation, among others.[1] Baryte commonly occurs in lead-zinc veins in limestones, in hot spring deposits, and with hematite ore. It is often associated with the minerals anglesite and celestine. It has also been identified in meteorites.[9]

Baryte has been found in locations in Cheshire, Connecticut, De Kalb, New York, Fort Wallace, New Mexico as well as quarried in Arkansas, Connecticut, Virginia, North Carolina, Georgia, Tennessee, Kentucky, Nevada, and Missouri in the USA.[2] Outside of the USA, localities include Baia Sprie, Romania, Westmoreland, Cornwell, Cumberland, Derbyshire, Muirshiel (where zinc was also retracted), Perthshire, Argyllshire and Surrey in the UK,[2] China, India, Morocco, Peru, Chile, Liberia, Turkey, Ireland (where it was actively mined on Benbulben[10]), Canada, Iran[11], Brazil, Greece, and Barberton Mountain Land, South Africa.[12]

Uses

Large barite crystals from Nevada, USA

Some 77% worldwide is used as a weighting agent for drilling fluids in oil and gas exploration. Other uses are in added-value applications which include the car, electronics, TV screen, rubber, and glass ceramics and paint industry, radiation shielding and medical applications (for example, a barium meal before a contrast CAT scan). Baryte is supplied in a variety of forms and the price depends on the amount of processing; filler applications commanding higher prices following intense physical processing by grinding and micronising, and there are further premiums for whiteness and brightness and color. Baryte is used in the manufacture of paints and paper.[7]

Historically baryte was used for the production of barium hydroxide for sugar refining, and as a white pigment for textiles, paper, and paint.[2]

Although baryte contains a "heavy" metal (barium), it is not considered to be a toxic chemical by most governments because of its extreme insolubility.

Paleothermometry

Baryte with Cerussite from Morocco

In the deep ocean, away from continental sources of sediment, pelagic baryte crystallizes out and forms a significant amount of the sediments. Since baryte has oxygen, systematics in the δ18O of these sediments have been used to help constrain paleotemperatures for oceanic crust. Similarly the variations in sulfur isotopes are also being exploited.[13]

References

  1. ^ a b c Hanor, J. (2000). "Barite-celestine geochemistry and environments of formation". Reviews in Mineralogy (Washington, DC: Mineralogical Society of America: Mineralogical Society of America) 40: 193–275. ISBN 0-939950-52-9. 
  2. ^ a b c d e f g h Dana, James Dwight; Ford, William Ebenezer (1915). Dana's Manual of Mineralogy for the Student of Elementary Mineralogy, the Mining Engineer, the Geologist, the Prospector, the Collector, Etc. (13 ed.). John Wiley & Sons, Inc.. pp. 299–300. http://www.archive.org/details/danasmanualmine00fordgoog. 
  3. ^ a b http://www.mindat.org/min-549.html Mindat
  4. ^ http://webmineral.com/data/Barite.shtml Webmineral data
  5. ^ http://rruff.geo.arizona.edu/doclib/hom/baryte.pdf Handbook of Mineralogy
  6. ^ History of the Bologna stone
  7. ^ a b USGS page for Barite
  8. ^ a b c d "International Mineralogical Association: Commission on New Minerals and Mineral Names". Mineralogical Magazine 38: 102–105. March 1971. doi:10.1180/minmag.1971.038.293.14. 
  9. ^ Rubin, Alan E. (March 1997). "Mineralogy of meteorite groups". Meteoritics & Planetary Science 32: 231–247. http://adsabs.harvard.edu/abs/1997M%26PS...32..231R. 
  10. ^ http://www.mhti.com/mines_in_ireland_files/benbulben.htm
  11. ^ http://www.highbeam.com/doc/1G1-129716432.html
  12. ^ Duchač, K. C; Hanor, J. S. (September 1987). "Origin and timing of the metasomatic silicification of an early Archaean komatiite sequence, Barberton Mountain Land, South Africa". Precambrian Research 37 (2): 125–146. doi:10.1016/0301-9268(87)90075-1. ISSN 0301-9268. 
  13. ^ Kastner, Miriam, Oceanic minerals: Their origin, nature of their environment, and significance, PNAS March 30, 1999 vol. 96 no. 7 3380-3387 http://www.pnas.org/content/96/7/3380.full

1911 encyclopedia

Up to date as of January 14, 2010

From LoveToKnow 1911

BARYTES, a widely distributed mineral composed of barium sulphate (BaSO 4). Its most striking feature and the one from which it derives its name barytes, barite (from the Greek Oapis, heavy) or heavy spar, is its weight. Its specific gravity of 4.5 is about twice as great as that of salt and of many other colourless, transparent and glassy minerals not unlike barytes in general appearance. The mineral is usually found in a state of considerable chemical purity, though small amounts of strontium and calcium sulphates may isomorphously replace the barium sulphate: ammonium sulphate is also sometimes present, whilst clay, silica, bituminous matter, &c., may be enclosed as impurities.

Crystals of barytes are orthorhombic and isomorphous with the strontium and lead sulphates (celestite and anglesite); they are usually very perfectly developed and present great variety of form. The simplest are rhomb-shaped tables (fig. I) bounded by the two faces of the basal pinacoid (c) and the four faces of the prism (m); the angle between the prism-faces (mm) is 78° 23', whilst that between c and m is go. The mineral has a very perfect cleavage parallel to the faces c and m, and the cleavage surfaces are perfectly smooth and bright. The crystals of prismatic habit represented in figs. 2 and 3 are bounded by the domes d and f and the basal pinacoid c; fig. 4 is a plan of a still FIG. 4.

more complex crystal. Twinning is represented only by twinlamellae, which are parallel to the planes m and f and are of secondary origin, having been produced by pressure.

Crystals of barytes may be transparent and colourless, or white and opaque, or of a yellow, brown, bluish or greenish 'colour. Well developed crystals are extremely common, but the mineral occurs also in a granular, earthy, or stalactitic condition. It is known as cawk in the Derbyshire lead mines. The "crested" or "cock's comb" barytes occurs as rounded aggregations of thin lamellar crystals.

Barytes is of common occurrence in metalliferous veins, especially those which yield ores of lead and silver; some of the largest and most perfect crystals of colourless barytes were obtained from the lead mines near Dufton in Westmorland. It is found also in beds of iron ore, and the haematite mines of the Cleator Moor district in west Cumberland have yielded many extremely fine crystals, specimens of which may be seen in all mineral collections. In the neighbourhood of Nottingham, and other places in the Midlands, barytes forms a cementing material in the Triassic sandstones; amber-coloured crystals of the same mineral are found in the fuller's earth at Nutfield in Surrey; and the septarian nodules in London Clay contain crystals of barytes as well as of calcite. Crystals are found as a rarity in the amygdaloidal cavities of igneous rocks.

Artificially prepared crystals of barytes may be obtained by allowing a solution of a soluble barium salt to diffuse slowly into a solution of a soluble sulphate. Barium chloride is present in some natural waters, and when this is the case the interaction of sulphates results in a deposition of barytes, as has occurred in the pipes and water-boxes of the Newcastle-on-Tyne coal mines.

Commercially, barytes is used in the preparation of barium compounds, as a body for certain kinds of paper and cloth, and as a white pigment ("permanent white"). The finely powdered and washed mineral is too crystalline and consequently of insufficient opacity to be used alone as a paint, and is therefore mixed with "white lead," of which material it is also used as an adulterant. (L. J. S.)


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