mineral
Amethyst
Amethyst (Silicon Dioxide, SiO2 with Iron impurities)
Hardness: 7 (Mohs scale); Color: Light to deep purple/violet; Luster: Vitreous/glassy; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65
- Hardness
- 7 (Mohs scale)
- Color
- Light to deep purple/violet
- Luster
- Vitreous/glassy
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Physical properties
Hardness: 7 (Mohs scale); Color: Light to deep purple/violet; Luster: Vitreous/glassy; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65
Formation & geological history
Formed in igneous or metamorphic rock cavities (geodes) through hydrothermal activity. The purple color is caused by irradiation of trivalent iron impurities within the quartz crystal lattice.
Uses & applications
Primary use is in jewelry, carvings, and as decorative collector specimens. It is also a popular stone in metaphysical/holistic practices.
Geological facts
Amethyst was considered one of the five cardinal gemstones until large deposits were found in Brazil. Its name comes from the Ancient Greek word 'amethystos', meaning 'not intoxicated', as it was believed to prevent drunkenness.
Field identification & locations
Identify by its characteristic purple color, hardness (it will scratch glass), and lack of cleavage. Commonly found in Brazil, Uruguay, Zambia, and Ontario, Canada.
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