Barite


Barite is a crystalline (orthorhombic) mineral occurring in globular, massive, rosette,
fibrous, and crystal forms. It has perfect cleavage. But the most important properties from the
point of view of industrial application are as follows.
1. Specific gravity: The most striking characteristic of barite is its high specific
gravity. The specific gravity of pure barite is 4.5 (c.f., magnetite 5.18) and this can
vary downward, depending on the impurities present. The mineral even feels heavy
in hand.
2. Sound-deadening ability: The high density enables barite to slow down
propagation of sound waves and it is thus an efficient sound-deadener.
3. Radiation adsorption- Barite can adsorb different kinds of radiation—X-rays,
neutrons, gamma-rays.
4. Colour and other optical properties: Pure barite is bright snow-white opaque to
transparent but impurities cause a wide variation in colour. Brightness of pure
barite as measured in terms of the reflectance of blue wave of light (wave length
457 micron) is 98.5 (c.f., for TiO2—a standard reference, the value is 97-98).
Whiteness of such barte as measured in terms of ‘L’ value is 99 (c.f., for TiO2—a
standard reference, the value is 98-100). Its lustre is vitreous to resinous. Refractive
index of barite is about 1.64.
5. Hardness and fracture: Its hardness varies from 3 to 3.5 on Mohs scale and it is
brittle, easily breaking with an uneven fracture. These properties make it nonabrasive
in character.
6. Chemical characteristics: Chemically, barite is BaSO4, but, in nature, it usually
contains impurities like SiO2, Al2O3, Fe2O3, clay, fluorite and carbonates. Barite
contains little or no soluble salts and it is insoluble in water and acid. It is chemically
inert with pH value 6-8 (pH value of 7 means neutrality).
7. Oil absorption: Its oil absorption is low.
8. Thermal property: Barite dissociates into barium sulphide (BaS) and oxygen at
13000C.