View source for Baryte

[[Image:Baryte Morocco.jpg|thumb|right|Baryte with Cerussite from Morocco]]
[[Image:Baryte Poland.jpg|thumb|right|Baryte with Galena and Hematite from Poland]]
[[Image:Barite-unit-cell-3D-balls.png|thumb|left|The unit cell of barite]]

'''Baryte''' ([[Barium|Ba]][[Sulfur|S]][[Oxygen|O]]<sub>4</sub>) is a [[mineral]] consisting of [[barium sulfate]]. It is generally white or [[color]]less, and is the main source of [[barium]]. '''Barite''' is the unofficial American spelling. The mineral is also called '''heavy spar''' or '''tiff'''.  The radiating form, sometimes referred to as Bologna Stone, attained some notoriety among [[Alchemy|alchemists]] for the [[phosphorescence|phosphorescent]] specimens found in the 1600s near [[Bologna]] by Vincenzo Cascariolo. Its [[Mohs hardness]] is 3, the [[refractive index]] is 1.63 and it has a [[specific gravity]] of 4.3-5. Its [[crystal structure]] is [[orthorhombic]].

Baryte commonly occurs in lead-zinc veins in [[limestone]]s, in hot spring deposits, and with [[hematite]] ore. It is often associated with the minerals [[anglesite]] and [[Celestine (mineral)|celestine]].

The name baryte is derived from the [[Greek language|Greek]] word ''βαρύς'' (heavy). In [[commerce]], the mineral is sometimes referred to as "barytes."  When the [[International Mineralogical Association]] formed in 1959 the American spelling "barite" was chosen as the official over the older "baryte".  This decision  was reversed in 1978<ref>Mineralogical Magazine 38, 104 (1971)</ref>.  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]].
[[Image:barite09.jpg|thumb|right|250px|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 (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.  Although baryte contains a "heavy" metal (barium), it is not considered to be a [[toxic]] chemical by most governments because of its extreme [[solubility|insolubility]].

==References==
{{reflist|2}}
* http://minerals.usgs.gov/minerals/pubs/commodity/barite/
* [http://www.mindat.org/min-549.html mindat page for Barite]
* [http://webmineral.com/data/Barite.shtml webmineral page for Barite]
* [http://www.isbc.unibo.it/Files/10_SE_BoStone.htm History of the Bologna stone]
* [http://www.barytes.org  Website of The Barytes Association]

[[Category:Barium minerals]]
[[Category:Sulfate minerals]]

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