mineral
Satin Spar (Gypsum)
Gypsum (Satin Spar variety) - CaSO4·2H2O
Hardness: 2 on the Mohs scale (can be scratched by a fingernail). Color: White, clear, or translucent. Luster: Silky or pearly. Crystal System: Monoclinic, forming fibrous and parallel crystalline structures.
- Hardness
- 2 on the Mohs scale (can be scratched by a fingernail)
- Color
- White, clear, or translucent
- Luster
- Silky or pearly
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Physical properties
Hardness: 2 on the Mohs scale (can be scratched by a fingernail). Color: White, clear, or translucent. Luster: Silky or pearly. Crystal System: Monoclinic, forming fibrous and parallel crystalline structures.
Formation & geological history
Formed as an evaporite mineral in lake and marine basin environments through the evaporation of saline water, often associated with sedimentary rock layers.
Uses & applications
Widely used in decorative carvings, metaphysical collections, optical fiber demonstrations due to fiber-optic visual effects, and in plaster or drywall production.
Geological facts
Satin spar exhibits strong natural fiber-optic properties (TV-rock effect), transmitting images along the direction of its fibrous crystals.
Field identification & locations
Identified by its extremely low hardness (easily scratched by a fingernail), silky sheen, and fibrous structure. Commonly found in Morocco, Mexico, USA, and UK.
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Mineral