mineral

Satin Spar Selenite

Gypsum (Calcium Sulfate Dihydrate) - CaSO4·2H2O

Hardness: 2 on Mohs scale (can be scratched by a fingernail). Color: White, pearly, or translucent with a milky sheen. Luster: Vitreous to pearly/silky. Crystal structure: Monoclinic, often fibrous. Cleavage: Perfect in one direction, produces thin sheets or fibers.

Hardness: 2 on Mohs scale (can be scratched by a fingernail)
Color: White, pearly, or translucent with a milky sheen
Luster: Vitreous to pearly/silky

Identified June 8, 2026More mineral →

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Physical properties

Formation & geological history

Formed as an evaporite mineral in sedimentary environments such as saline lakes, lagoons, and caves where calcium-rich water evaporates. It can form in various geological ages from the Silurian to the present.

Uses & applications

Commonly used in metaphysical practices, ornamental carvings, and interior decor. Industrial gypsum is used for drywall, plaster, and as a soil conditioner in agriculture.

Geological facts

Selenite is named after the Greek word 'selene' meaning moon, due to its moon-like ethereal glow. The famous 'Cueva de los Cristales' in Mexico contains selenite crystals over 30 feet long.

Field identification & locations

Identify in the field by its softness (it is easily scratched by a fingernail) and fibrous, silky appearance. Found globally, with major deposits in Morocco, Mexico, USA, and Brazil. Collectors should avoid water as it can dissolve or dull over time.

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