mineral

Selenite

Gypsum (Calcium Sulfate Dihydrate, CaSO4·2H2O)

AI-generated identification · may be incorrect

Hardness: 2 (can be scratched by a fingernail). Color: Colorless to white. Luster: Vitreous to pearly. Crystal Structure: Monoclinic, often tabular or bladed. Cleavage: Perfect (one direction). Specific Gravity: 2.3.

Hardness: 2 (can be scratched by a fingernail)
Color: Colorless to white
Luster: Vitreous to pearly

Identified June 28, 2026More mineral →

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Physical properties

Formation & geological history

Formed as an evaporite mineral in sedimentary environments such as marine basins or saline lakes through the evaporation of water. Deposits can range from millions of years old to relatively modern formations in arid regions.

Uses & applications

Used in the production of plaster of Paris, wallboard (drywall), soil fertilizer, and as a filler in paper and paints. Transparent varieties like the one pictured are popular for metaphysical use and ornamental collecting.

Geological facts

The famous Naica Mine in Mexico contains selenite crystals over 30 feet long. Selenite is extremely water-soluble; if left in water, it will eventually dissolve. It is the defining mineral for hardness level 2 on the Mohs scale.

Field identification & locations

Identify by its extreme softness (scratches with a fingernail) and its tendency to peel into thin sheets or break along flat cleavage planes. Commonly found in desert regions, ancient seabed deposits, and near hot springs.