mineral

Satin Spar Selenite

Gypsum (Calcium Sulfate Dihydrate, CaSO4·2H2O)

Hardness: 2 (Mohs scale, can be scratched by a fingernail); Color: Pearly white to peach/orange; Luster: Silky or pearly; Crystal Structure: Monoclinic; Cleavage: Perfect in one direction; Specific Gravity: 2.3

Hardness: 2 (Mohs scale, can be scratched by a fingernail)
Color: Pearly white to peach/orange
Luster: Silky or pearly

Identified June 8, 2026More mineral →

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Physical properties

Formation & geological history

Formed in evaporative environments where saline water evaporates, leaving behind mineral deposits. Commonly found in sedimentary beds and prehistoric lake bottoms.

Uses & applications

Used in plaster of Paris, drywall/wallboard construction, soil fertilizer, and widely as a 'cleansing' stone in metaphysical communities and collector decor.

Geological facts

Satin spar is often confused with true Selenite (which is transparent). It gets its 'satin' name from the way light reflects off its fibrous crystal structure, creating a cat-eye effect known as chatoyancy.

Field identification & locations

Identify by its extreme softness (scratches with a fingernail) and fibrous, silky appearance. Found globally in places like Morocco, Mexico, and the USA (Utah). Do not soak in water as it can dissolve or lose its luster.

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