mineral
Amethyst on Quartz
Crystalline Silicon Dioxide with trace amounts of Iron (SiO2 + Fe3+)
Hardness: 7 (Mohs scale), Color: light purple with white matrix, Luster: Vitreous, Crystal Structure: Trigonal/Hexagonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65
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Physical properties
Hardness: 7 (Mohs scale), Color: light purple with white matrix, Luster: Vitreous, Crystal Structure: Trigonal/Hexagonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65
Formation & geological history
Formed in hydrothermal veins and volcanic cavities (geodes) where iron-bearing silica-rich fluids crystallize. The purple color is the result of irradiation and iron impurities. Deposits range from millions to billions of years old.
Uses & applications
Widely used for ornamental jewelry, metaphysical collecting, and as a semi-precious gemstone. High-quality clusters are prized for home decor.
Geological facts
Amethyst was considered a cardinal gem until large deposits were found in Brazil in the 1700s. Its name comes from the Ancient Greek 'amethystos', meaning 'not intoxicated', as it was believed to prevent drunkenness.
Field identification & locations
Identify by its 6-sided crystalline prism structure and purple hue. It can be found globally with major deposits in Brazil and Uruguay. For identification, check hardness (should scratch glass but not topaz).
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