mineral
Amethyst
Quartz (SiO2) with iron impurities
Hardness: 7 (Mohs scale), Color: Purple to violet with white quartz banding, 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 with white quartz banding, Luster: Vitreous/glassy, Crystal structure: Hexagonal/Trigonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65
Formation & geological history
Formed in hydrothermal veins or cavities (geodes) when silica-rich water deposits crystals. The purple color is caused by irradiation of trivalent iron (Fe3+) within the quartz structure. Most specimens are from the Jurassic to Cretaceous periods.
Uses & applications
Widely used in jewelry (rings, necklaces), ornamental carvings, as a healing crystal in metaphysical practices, and as a popular collector's mineral.
Geological facts
Amethyst is the birthstone for February. The name comes from the Ancient Greek word 'amethystos', meaning 'not intoxicated', as it was believed to prevent drunkenness.
Field identification & locations
Identified by its signature purple color and quartz-like hardness. Look for white 'chevron' or 'v' patterns in tumbled stones. Common locations include Brazil, Uruguay, and Zambia.
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sedimentary
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Metamorphic
Epidote
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metamorphic
Gypsum (variety Selenite or Alabaster)
Calcium sulfate dihydrate (CaSO4·2H2O)
Mineral
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Nephrite
Mineral/Rock
Granite
Granite (Phaneritic intrusive igneous rock)
igneous