mineral

Selenite (Satin Spar Variety)

Gypsum (CaSO4·2H2O)

Hardness: 2 (can be scratched by a fingernail), Color: White to translucent/pearly, Luster: Silky or pearly, Crystal structure: Monoclinic (fibrous habit), Cleavage: Perfect in one direction.

Identified July 13, 2026More mineral →

Explore Selenite (Satin Spar Variety) in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness: 2 (can be scratched by a fingernail), Color: White to translucent/pearly, Luster: Silky or pearly, Crystal structure: Monoclinic (fibrous habit), Cleavage: Perfect in one direction.

Formation & geological history

Formed as an evaporite mineral in ancient seabeds or through the hydration of anhydrite. This fibrous variety often grows in veins via hydrothermal or sedimentary processes where calcium-rich water evaporates.

Uses & applications

Used in the manufacture of plaster and drywall (gypsum), as a soil conditioner, for ornamental carvings, and widely sold in the metaphysical industry as 'cleansing' wands.

Geological facts

The name 'Selenite' comes from the Greek word 'selene', meaning moon, due to its soft glow. This specimen displays the 'satin spar' fibrous habit, which creates a cat's-eye (chatoyancy) effect when polished.

Field identification & locations

Identify by its extreme softness (scratched by nail) and fibrous, silky appearance. Commonly found in Morocco, Mexico, and the USA. Collectors should keep it dry as it can slightly dissolve or degrade in water over long periods.