mineral

Satin Spar Selenite

Gypsum (CaSO4·2H2O)

Hardness: 2 (Mohs), Color: White or pearly, Luster: Silky or pearly, Crystal structure: Monoclinic, Cleavage: Perfect, Specific Gravity: 2.3

Identified May 23, 2026More mineral →

Identify your own rocks.

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

App Store Google Play

Physical properties

Hardness: 2 (Mohs), Color: White or pearly, Luster: Silky or pearly, Crystal structure: Monoclinic, Cleavage: Perfect, Specific Gravity: 2.3

Formation & geological history

Forms as an evaporite mineral in sedimentary environments such as saline lakes, lagoons, and caves where calcium-rich water evaporates.

Uses & applications

Used in plaster of Paris, wallboard (drywall), soil fertilizer, and carved into decorative objects or palm stones for the metaphysical market.

Geological facts

Satin spar is often confused with 'true' selenite, which refers to the transparent variety. It exhibits a fiber-optic effect where light travels along its internal structure.

Field identification & locations

Identify by its extreme softness (can be scratched by a fingernail) and its distinctive fibrous, silky appearance. Commonly found in Morocco, USA, Mexico, and Brazil.