mineral

Selenite

Gypsum (CaSO4·2H2O)

Hardness of 2 on the Mohs scale, transparent to translucent white or colorless, pearly to vitreous luster, monoclinic crystal system, perfect cleavage in one direction, specific gravity around 2.3

Identified July 31, 2026More mineral →

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Physical properties

Hardness of 2 on the Mohs scale, transparent to translucent white or colorless, pearly to vitreous luster, monoclinic crystal system, perfect cleavage in one direction, specific gravity around 2.3

Formation & geological history

Formed as an evaporite mineral from the precipitation of calcium sulfate-rich water in evaporating bodies of water such as lakes and seas

Uses & applications

Commonly used in crystal healing, interior decoration, lamps, and occasionally in plaster of Paris or gypsum board production

Geological facts

Selenite is named after the Greek goddess of the moon, Selene, due to its moon-like glow. It is so soft that it can easily be scratched with a fingernail.

Field identification & locations

Easily identified by its very low hardness (can be scratched by a fingernail), fibrous texture, and pearly luster. Found worldwide, with major deposits in Mexico, Morocco, and the USA.