mineral
Amethyst
Silicon Dioxide (SiO2) with iron impurities
Hardness: 7 (Mohs); Color: Pale violet to deep purple; Luster: Vitreous; Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65
- Hardness
- 7 (Mohs)
- Color
- Pale violet to deep purple
- Luster
- Vitreous
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Physical properties
Hardness: 7 (Mohs); Color: Pale violet to deep purple; Luster: Vitreous; Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65
Formation & geological history
Formed in hydrothermal veins or as linings in volcanic geodes. The purple color is caused by irradiation, iron impurities, and the presence of trace elements. Most specimens are from the Cenozoic era, though specific ages vary by location.
Uses & applications
Primarily used in jewelry (as a gemstone), ornamental carvings, and widely sought after by crystal collectors for aesthetic and metaphysical purposes.
Geological facts
Until the 18th century, amethyst was considered one of the 'cardinal gems' and was as valuable as diamond. The Greeks believed it could prevent intoxication, leading to the name 'amethystos' meaning 'not drunken.'
Field identification & locations
Identify in the field by its distinct purple hue and quartz-like fracture. Commonly found in Brazil, Uruguay, Madagascar, and the United States (Arizona). Collectors should look for deep, uniform color and clarity.
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