Dictionary: barite   (bâr'īt, băr'-) also barytes (bə-rī'tēz)

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.

(click to enlarge)
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 with Cerussite from Morocco

Baryte with Galena and Hematite from Poland

The unit cell of barite

Barite (BaSO₄) is a mineral consisting of barium sulfate. It is generally white or colorless, and is the main source of barium. Baryte is the British spelling, and the mineral is also called heavy spar. The radiating form, sometimes referred to as Bologna Stone, attained some notoriety among alchemists for the phosphorescent specimens found in the 1600s near Bologna, Italy by one Mr. 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.

Barite 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.

The name barite is derived from the Greek word βαρύς (heavy). In commerce, the mineral is sometimes referred to as "barytes." The term "primary barite" refers to the first marketable product, which includes crude barite (run of mine) and the products of simple beneficiation methods, such as washing, jigging, heavy media separation, tabling, flotation, and magnetic separation. Most crude barite requires some upgrading to minimum purity or density. Barite that is used as an aggregate in a "heavy" cement is crushed and screened to a uniform size. Most barite 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.

Barite is used in the manufacture of paints and paper. Although barite contains a "heavy" metal (barium), it is not considered to be a toxic chemical by most governments because of its extreme insolubility.

External links

Large barite crystals from Nevada, USA

• mindat page for Barite
• webmineral page for Barite
• History of the Bologna stone

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