mineral
Prehnite
Prehnite (Ca2Al(AlSi3O10)(OH)2)
AI-generated identification · may be incorrectHardness: 6-6.5 Mohs scale; Color: Pale green to yellow-green; Luster: Vitreous to pearly; Crystal structure: Orthorhombic; Cleavage: Good; Specific Gravity: 2.80-2.95
- Hardness
- 6-6
- Color
- Pale green to yellow-green
- Luster
- Vitreous to pearly
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Physical properties
Hardness: 6-6.5 Mohs scale; Color: Pale green to yellow-green; Luster: Vitreous to pearly; Crystal structure: Orthorhombic; Cleavage: Good; Specific Gravity: 2.80-2.95
Formation & geological history
Formed primarily in the cavities of mafic volcanic rocks (like basalts). Created by low-grade metamorphism or hydrothermal activity as a secondary mineral. Often occurs in botryoidal or globular habits.
Uses & applications
Popular as a semi-precious gemstone for jewelry (beads, cabochons), a collector's specimen, and occasionally used as an ornamental stone.
Geological facts
Prehnite was the first mineral to be named after a person, Colonel Hendrik Von Prehn, who brought the mineral from South Africa in 1774. It is sometimes called 'Cape Emerald' due to its color.
Field identification & locations
Identified by its distinctive light green color and bubbly 'botryoidal' appearance. Often found associated with Zeolites. Notable locations include South Africa, Australia, and Paterson, New York.
