barite

A yellow, white, or colorless crystalline mineral of barium sulfate, BaSO₄, that is used in paint and as the chief source of barium chemicals. Also called heavy spar.

[Greek barus, heavy + –ITE¹.]

An orthorhombic mineral with chemical composition BaSO₄. It possesses one perfect cleavage, and two good cleavages, as do the isostructural minerals. The mineral has a specific gravity of approximately 4.5, and is relatively soft, approximately 3 on Mohs scale. The color ranges through white to yellowish, gray, pale blue, or brown, and a thin section is colorless.

Barite is often an accessory mineral in hydrothermal vein systems, but frequently occurs as concretions or cavity fillings in sedimentary limestones. It also occurs as a residual product of limestone weathering and in hot spring deposits. It occasionally occurs as extensive beds in evaporite deposits. Occurrences of barite are extensive. It is found as a vein mineral associated with zinc and lead ores in Derbyshire, England. Large deposits occur at Andalusia, Spain. Commercial residual deposits occur in limestones throughout the Appalachian states such as Georgia, Tennessee, and Kentucky. It also occurred in substantial amounts in the galena ore deposits in Wisconsin and Missouri.

Since barite is dense and relatively soft, its principal use is as a weighting agent in rotary well-drilling fluids. It is the major ore of barium salts, used in glass manufacture, as a filler in paint, and, owing to the presence of a heavy metal and inertness, as an absorber of radiation in x-ray examination of the gastrointestinal tract.

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Sample of crested barite from Missouri (credit: Joseph and Helen Guetterman collection; photograph, John H. Gerard)

Most common barium mineral, barium sulfate (BaSO₄). It commonly forms as platy crystals (known as crested barite). Barite is abundant in parts of Spain, Germany, and the U.S. Commercially, ground barite is used in oil well and gas well drilling muds; in the preparation of barium compounds; as a filler for paper, cloth, and phonograph records; as a white pigment; and as an inert material in coloured paints.

For more information on barite, visit Britannica.com.

A mineral used in concrete as an aggregate, esp. for the construction of high-density radiation shielding; also called barium sulfate.

Environment

A very common mineral of greatly varying habit and a variety of parageneses; in sedimentary rocks and a frequent late gangue mineral in ore veins.

Crystals commonly tabular, often very large. Also prismatic, equidimensional, in featherlike and crested groups, concretionary masses, "desert roses," even stalactitic, fine-grained, massive, and rocklike.

Crystals colorless to bluish, yellow, reddish brown, also fine-grained and earthy. Luster glassy; hardness 3-3Ɖ; specific gravity 4.3-4.6; fracture uneven; cleavage several perfect basal and prismatic, and a fair side pinacoid. Brittle; transparent to translucent; sometimes fluorescent (see tests).

Barium sulfate (65.7% BaO, 34.3% SO ₃ ).

Decrepitates, whitens, but fuses only with some difficulty. After intense heating, whitened assay fluoresces, usually bright orange. Gives sulfur test with sodium carbonate flux.

The unusually high gravity in such a light-colored mineral is usually sufficiently significant. Distinguished from calcite by insolubility in acid; from feldspar by its softness; from celestite and anhydrite by orange fluorescence after firing and the green flame color; and from fluorite by lack of typical fluorite fluorescence, cleavages, and crystal shape.

Although barite often is an accompanying mineral in a sulfide ore vein, it is even more common in sedimentary rocks, where it forms concretionary nodules and free-growing crystals in open spaces. Veins of almost pure barite have been mined in several localities. The finest large barite crystals have come from Cumberland, England; single many-faced free-growing crystals were as much as 8 in. (20 cm) long. The British occurrences are notable for delicate coloring and well-formed crystals. There are many other fine localities, however. In Baia Sprie (Felsöbanya), Romania, it is intimately associated with stibnite needles, usually in flat colorless or yellowish crystals. In Morocco and Egypt it is found in unattractive but giant, foot-long (30 cm) crystals. Other occurrences abroad are too numerous to mention.

In the U.S. it is mined in the Midwest, as in Missouri. There white-bladed masses are found where the soil contacts the undecomposed limestone--the barite having settled as the enclosing rock weathered away. Good white to clear crystals, some a foot (30 cm) long, have also been found in Missouri. It is found in perfect imitative "roses" of a red-brown color and sandy texture near Norman, Oklahoma. Fine crusts of blue crystals are found in veins in soft sediments near Stoneham, Colorado. Great concretions, known as septarian nodules, found in the badlands of South Dakota, contain up to 4-in. (10 cm) fluorescent, transparent, amber-colored crystals in the cracks.

An important commercial mineral; widely used as a pigment, in the preparation of lithopone (a pigment also known as zinc sulfide white), and as a filler for paper and cloth. Barite "mud" is poured into deep oil wells to buoy up the drilling tools. Several hundred years ago, a massive, concretionary variety of barite from Italy was found to phosphoresce on light heating, and was called Bologna stone from its locale of discovery. It was, of course, of great interest to the alchemists, the founders of chemistry, who were trying to make gold from the base metals.

Baryte
General
Category	Anhydrus Sulfates, Barite Group[1]
Chemical formula	BaSO4
Identification
Color	colorless, white, light shades of blue, yellow red[1]
Crystal habit	tabular parallel to base, often diamond shaped[1]
Crystal system	orthorhombic[1]
Cleavage	perfect cleavage parallel to base and prism faces[1]
Mohs Scale hardness	3-3.5[1]
Luster	Vitreous, Pearly [1]
Diaphaneity	transparent to opaque[1]
Specific gravity	4.3-5
Density	4.48 g/cm3[2]
Optical properties	biaxial positive
Refractive index	1.63
Birefringence	0.012
Fusibility	4, yellowish green Barium flame[1]
Diagnostic features	white color, high specific gravity, characteristic cleavage and crystals [1]
Solubility	low

Baryte with Galena and Hematite from Poland

The unit cell of barite

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

Contents 1 Names and history 1.1 Other names 2 Mineral associations and locations 3 Uses 4 References

Names and history

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^[3].

The name baryte is derived from the Greek word βαρύς (heavy). The American spelling barite^[1] is used by USGS ^[4] and more often used in modern Scientific 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^[5], 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.

Other names

Baryte has gone by other names such as barytine^[5], barytite^[5], scbwerspath^[5], barytes^[1], Heavy Spar^[1], or tiff^{[citation needed]}.

Mineral associations and locations

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.^[2] Baryte commonly occurs in lead-zinc veins in limestones, in hot spring deposits, and with hematite ore, and in some meteorites. It is often associated with the minerals anglesite and celestine. It has also been identified in meteorites.^[6]

Baryte has been found in locations in Cheshire, Connecticut, De Kalb, New York, Fort Wallace, New Mexico as well as quarried in Connecticut, Virginia, North Carolina, Georgia, Tennessee, Kentucky, and Missouri in the USA^[1]. Outside of the USA, localities include Baia Sprie, Romania, Westmoreland, Cornwell, Cumberland, Derbyshire, and Surrey in the UK^[1], and Barberton Mountain Land, South Africa^[7]

Large barite crystals from Nevada, USA

Baryte with Cerussite from Morocco

Uses

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 (barium meals). 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 colour. Baryte is used in the manufacture of paints and paper.^[4]

Historically baryte was used for the production of barium hydroxide for sugar refining, and as a white pigment for textiles, paper, and paint^[1].

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

References

1. ^ ^{a b c d e f g h i j k l m n o p q} 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. 
2. ^ ^{a b c} Hanor, J. (2000). "Barite-celestine geochemistry and enviroments of formation". Reviews in Mineralogy 40: 193-275. ISBN 0-939950-52-9. 
3. ^ History of the Bologna stone
4. ^ ^{a b} USGS page for Barite
5. ^ ^{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. 
6. ^ Rubin, Alan E. (March 1997). "Mineralogy of meteorite groups". Meteoritics & Planetary Science 32: 231-247. http://adsabs.harvard.edu/abs/1997M%26PS...32..231R. 
7. ^ 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. 

• mindat page for Barite
• webmineral page for Barite
• Website of The Barytes Association

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