Anhydrite
Species
Common · CaSO₄
Anhydrous calcium sulfate deposited in evaporite sequences. Absorbs water to convert to gypsum, expanding in volume. Found in association with halite and gypsum in marine evaporite deposits worldwide.
Identity
- Formula
- CaSO₄
- Chemical class
- Sulfate
- Also known as
- Anhydrous gypsum
Crystallography
- Crystal system
- Orthorhombic
- Habits
- Massive, Tabular, Granular
- Fracture
- Uneven
Physical properties
- Mohs hardness
- 3.5
- Density
- 2.98 g/cm³
- Luster
- Vitreous, Pearly
- Colors
- white, gray, blue, pink, violet
- Streak
- white
- Transparency
- Transparent, Translucent
Geology
- Origins
- Sedimentary
- Host rocks
- Limestone and chalk, Salt beds
- Associated minerals
- Gypsum, Halite, Calcite, Sulfur
- Found in
- Rock gypsum, Rock salt, Evaporite deposit, Porphyry copper deposit
- Geography
- worldwide
Classification
- Rarity
- Common
- Gem quality
- No
Sources
- M. Pasero and others, IMA Commission on New Minerals, Nomenclature and Classification, The New IMA List of Minerals, updated September 2026. International Mineralogical Association (CNMNC), 2026.
- Anhydrite. Mindat.org (Hudson Institute of Mineralogy).
- J. W. Anthony, R. A. Bideaux, K. W. Bladh, M. C. Nichols, Anhydrite. Mineral Data Publishing, Handbook of Mineralogy, 2001.
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