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David

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anhydrite

anhydrite

Anhydrite specimen from Chihuahua, Mexico, in the Harvard Museum of Natural History. Source: Wikipedia.


Anhydrite is a mineral form of anhydrous calcium sulfate (CaSO4, see calcium), occurring worldwide as white-gray masses of orthorhombic crystals. Thick beds of anhydrite are formed where old seawater lagoons have evaporated.

 

Anhydrite is used in producing sulfuric acid and ammonium sulfate and as a drying agent. Hardness 3–3.5, specific gravity 3. See also gypsum.