mineral
Satin Spar Gypsum (Satin Spar Selenite)
Hydrous calcium sulfate (CaSO4%2H2O)
Mohs hardness of 2 (can be scratched easily with a fingernail), silky to pearly luster, fibrous structure, perfect cleavage, white to translucent color, soft and lightweight.
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Physical properties
Mohs hardness of 2 (can be scratched easily with a fingernail), silky to pearly luster, fibrous structure, perfect cleavage, white to translucent color, soft and lightweight.
Formation & geological history
Forms as an evaporite mineral in lake and marine basins where saline waters evaporate, often found in association with halite and anhydrite.
Uses & applications
Widely used in ornamental carvings, crystal healing, metaphysical wands, charging plates, and industrially for plaster of Paris, drywall, and soil conditioning.
Geological facts
Though commonly sold as 'selenite' in the gem trade, this fibrous variety is technically 'satin spar'. It displays a chatoyant ('cat's-eye') effect along its fibrous axis.
Field identification & locations
Identified by its extreme softness (scratched by a fingernail) and distinct parallel fibrous structure. Major deposits are found in Morocco, Mexico, USA, and Madagascar.
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Metamorphic
Sandstone with Mineral Veining or Crust
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sedimentary
Potassium Feldspar (Orthoclase)
Orthoclase (KAlSi3O8)
mineral
Gypsum (variety Selenite or Alabaster)
Calcium sulfate dihydrate (CaSO4·2H2O)
Mineral
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Nephrite
Mineral/Rock