mineral
Prehnite
Prehnite (Ca2Al2Si3O10(OH)2)
AI-generated identification · may be incorrectHardness: 6-6.5 on the Mohs scale. Color: Pale green to yellow-green. Luster: Vitreous to pearly. Crystal structure: Orthorhombic, usually occurring in botryoidal or globular habits. Cleavage: Good in one direction.
- Hardness
- 6-6
- Color
- Pale green to yellow-green
- Luster
- Vitreous to pearly
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Physical properties
Hardness: 6-6.5 on the Mohs scale. Color: Pale green to yellow-green. Luster: Vitreous to pearly. Crystal structure: Orthorhombic, usually occurring in botryoidal or globular habits. Cleavage: Good in one direction.
Formation & geological history
Formed as a secondary mineral in cavities of mafic volcanic rocks (basalt). It typically forms from hydrothermal activity during low-grade metamorphism.
Uses & applications
Used primarily as a gemstone for jewelry, carvings, and as a popular mineral specimen for collectors. It has minor historical use as an ornamental stone.
Geological facts
Prehnite was the first mineral to be named after a person, Colonel Hendrik Von Prehn, who discovered it at the Cape of Good Hope in South Africa in 1788.
Field identification & locations
Identify in the field by its distinct 'grape-like' (botryoidal) clusters and translucent pale green color. Often found associated with zeolites or epidote in basaltic vugs.
