mineral
Amethyst
Silicon Dioxide (SiO2)
Hardness: 7 (Mohs scale), Color: Purple to violet, Luster: Vitreous/glassy, Crystal structure: Hexagonal (Trigonal), Cleavage: None (Conchoidal fracture), Specific gravity: 2.65
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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
Formed in hydrothermal veins and basaltic cavities (vugs) through the precipitation of silica from hot groundwater. The purple color is caused by trace amounts of iron and natural irradiation.
Uses & applications
Widely used for jewelry, decorative carvings, and as a popular specimen for crystal collectors. Historically used to prevent intoxication.
Geological facts
Amethyst was considered a 'Precious Stone' alongside Diamond, Sapphire, Ruby, and Emerald until large deposits were found in Brazil in the 19th century. Its name comes from the Greek 'amethystos', meaning 'not intoxicated'.
Field identification & locations
Identify by its characteristic purple color and hexagonal crystal habits. Often found inside geodes. Common locations include Brazil, Uruguay, Zambia, and South Korea.
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