mineral

Satin Spar Selenite (Peach Calcite/Peach Gypsum)

Hydrated Calcium Sulfate (CaSO4·2H2O)

Hardness: 2 (very soft); Color: Peach to orange-pink; Luster: Pearly, silky, or vitreous; Crystal Structure: Monoclinic; Cleavage: Perfect; Specific Gravity: 2.3

Hardness: 2 (very soft)
Color: Peach to orange-pink
Luster: Pearly, silky, or vitreous

Identified January 7, 2026More mineral →

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Physical properties

Hardness: 2 (very soft); Color: Peach to orange-pink; Luster: Pearly, silky, or vitreous; Crystal Structure: Monoclinic; Cleavage: Perfect; Specific Gravity: 2.3

Formation & geological history

Formed primarily in evaporative environments such as ancient lake beds or seafloors where sea water rich in calcium and sulfate evaporated. The peach color is often caused by trace inclusions of hematite or sand.

Uses & applications

Used extensively for ornamental carvings, palm stones in crystal healing, jewelry (though fragile), and commercially as a source of gypsum for plaster and wallboard.

Geological facts

Satin spar is a fibrous variety of gypsum that exhibits a unique 'cat's eye' chatoyancy when polished. It is so soft that it can be scratched with a fingernail.

Field identification & locations

Identify by its extreme softness (scratches with a fingernail), silky fibrous texture, and pearly luster. Commonly found in Morocco, Mexico, and the USA (Utah/Arizona).

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