mineral
Amethyst
Silicon Dioxide (SiO2) with iron impurities
Hardness of 7 on Mohs scale, deep purple color, vitreous (glassy) luster, hexagonal crystal system, conchoidal fracture, no distinct cleavage, specific gravity around 2.65.
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Physical properties
Hardness of 7 on Mohs scale, deep purple color, vitreous (glassy) luster, hexagonal crystal system, conchoidal fracture, no distinct cleavage, specific gravity around 2.65.
Formation & geological history
Formed inside volcanic rocks or geodes when silica-rich fluids deposit quartz crystals in gas cavities. The signature purple color comes from trace amounts of iron combined with natural radiation exposure over geological time.
Uses & applications
Extensively used in jewelry making (rings, necklaces, beads), lapidary arts, decorative carvings, and as a popular specimen for rock and mineral collectors.
Geological facts
Amethyst is the official birthstone for February. In ancient times, the Greeks believed it could prevent intoxication, naming it from 'amethystos', meaning 'not drunken'. Large geodes are often found in South America, particularly Brazil and Uruguay.
Field identification & locations
Identified by its distinctive purple hue, hardness (scratches glass, cannot be scratched by a steel blade), glassy luster, and shell-like fracture patterns. Commonly found in Brazil, Uruguay, Madagascar, and Zambia.
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