mineral

Raw selenite (gypsum)

Gypsum, CaSO₄·2H₂O; translucent variety selenite

AI-generated identification · may be incorrect

Typically colorless to white, pearly or vitreous, with prominent perfect cleavage and a platy/fibrous crystal structure; Mohs hardness 2, specific gravity about 2.3. The specimen appears translucent and cleavage-dominated, though image detail is limited.

Identified August 10, 2026More mineral →

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Physical properties

Formation & geological history

Forms when evaporating saline waters precipitate calcium sulfate, or in hydrothermal and sedimentary settings; deposits range from ancient to modern, commonly Permian through Cenozoic. It is not technically an igneous, sedimentary, or metamorphic rock, but a mineral specimen.

Uses & applications

Used to manufacture plaster, drywall, cement, and soil amendments; clear attractive pieces are sold as inexpensive decorative and collecting specimens. It is generally too soft for durable jewelry.

Geological facts

Selenite can be scratched easily with a fingernail and may split into thin sheets. “Satin spar” is fibrous gypsum, while “desert rose” is a rosette-shaped gypsum variety.

Field identification & locations

Common localities include Mexico, Morocco, Spain, the United States, and Australia. Confirm with a fingernail scratch, very low weight, pearly cleavage, and lack of fizz in dilute acid.