mineral
Gypsum (Desert Rose or Selenite variety)
Calcium Sulfate Dihydrate (CaSO4·2H2O)
Hardness: 2 on Mohs scale (can be scratched by a fingernail). Color: Tan, brown, or grayish. Luster: Pearly to vitreous. Crystal structure: Monoclinic. Cleavage: Perfect in one direction.
- Hardness
- 2 on Mohs scale (can be scratched by a fingernail)
- Color
- Tan, brown, or grayish
- Luster
- Pearly to vitreous
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Physical properties
Hardness: 2 on Mohs scale (can be scratched by a fingernail). Color: Tan, brown, or grayish. Luster: Pearly to vitreous. Crystal structure: Monoclinic. Cleavage: Perfect in one direction.
Formation & geological history
Evaporite mineral formed by the evaporation of seawater or saline lake water in arid basins. Often found in sedimentary environments such as salt flats and clay beds.
Uses & applications
Primary source of plaster of paris, drywall, and fertilizer. Also used as a soil conditioner and by collectors for unique crystal habits.
Geological facts
Gypsum is one of the most common minerals in sedimentary environments; it can form massive beds and is soft enough to be carved into intricate sculptures (alabaster).
Field identification & locations
Identified by its extreme softness and characteristic monoclinic crystal forms. Found globally in arid regions like the Sahara, US Southwest, and Mexico.
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sedimentary
Sandstone with Mineral Veining or Crust
Sedimentary Sandstone (mostly SiO2 with Fe2O3 tinting)
sedimentary
Schist
Schist
Metamorphic
Potassium Feldspar (Orthoclase)
Orthoclase (KAlSi3O8)
mineral
Gypsum (variety Selenite or Alabaster)
Calcium sulfate dihydrate (CaSO4·2H2O)
Mineral
Nephrite Jade
Nephrite
Mineral/Rock