mineral
Amethyst
SiO2 (Silicon Dioxide with iron impurities)
Hardness: 7 (Mohs scale); Color: Purple to violet; Luster: Vitreous/glassy; Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65
- Hardness
- 7 (Mohs scale)
- Color
- Purple to violet
- Luster
- Vitreous/glassy
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Physical properties
Hardness: 7 (Mohs scale); Color: Purple to violet; Luster: Vitreous/glassy; Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65
Formation & geological history
Forms in geothermal environments, specifically inside volcanic rock cavities (geodes) or hydrothermal veins. Its purple color is produced by gamma irradiation of trace iron minerals in the quartz lattice.
Uses & applications
Widely used in jewelry (faceting, beads), decorative home decor (geode cathedrals), and mineral collecting. Historically used for amulets and carvings.
Geological facts
The name comes from the ancient Greek 'amethystos', meaning 'not intoxicated', as it was believed to protect its owner from drunkenness. It was once considered one of the 'Cardinal Gems' alongside diamond and ruby until vast deposits were found in Brazil.
Field identification & locations
Identify by its six-sided crystal points and purple hue. Common in volcanic regions like Brazil and Uruguay. Collectors should look for deep, saturated 'Siberian' purple color and clarity.
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Schist
Schist
Metamorphic
Potassium Feldspar (Orthoclase)
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Mineral
Epidote
Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)
metamorphic