mineral

Likely selenite (gypsum) crystal

Gypsum, CaSO₄·2H₂O; selenite is its transparent-to-translucent crystalline variety

AI-generated identification · may be incorrect

White to colorless, translucent, with a pearly or glassy luster and prominent cleavage; monoclinic crystals. Mohs hardness 2 and specific gravity about 2.3; the specimen’s blocky, splintered appearance is consistent with gypsum, though the photo alone cannot confirm it.

Identified October 9, 2026More mineral →

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Physical properties

Formation & geological history

Forms when calcium- and sulfate-rich water evaporates, or in sedimentary deposits and hydrothermal settings. Gypsum deposits range from recent to hundreds of millions of years old; the specimen’s age and source cannot be determined visually.

Uses & applications

Gypsum is used in drywall, plaster, cement, and agriculture; clear selenite crystals are collected and sometimes used decoratively.

Geological facts

Gypsum is soft enough to be scratched by a fingernail and can be cut into thin, flexible-looking sheets called satin spar.

Field identification & locations

Look for very low hardness, pale color, and easy cleavage; common deposits occur in arid evaporite basins worldwide. Keep it dry and handle gently, since gypsum is soft and can be damaged by water or abrasion.