mineral
Amethyst
Silicon Dioxide (SiO2) with iron impurities
Hardness 7 on Mohs scale; Color ranges from light lavender to deep violet; Vitreous (glassy) luster; Hexagonal/Trigonal crystal system; Conchoidal fracture; No cleavage.
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Physical properties
Hardness 7 on Mohs scale; Color ranges from light lavender to deep violet; Vitreous (glassy) luster; Hexagonal/Trigonal crystal system; Conchoidal fracture; No cleavage.
Formation & geological history
Forms in volcanic rocks, specifically inside geodes and cavities where silica-rich hydrothermal fluids crystallize over time. Formation can take millions of years.
Uses & applications
Primarily used in jewelry (faceting, beads, cabochons), ornamental decoration, and as a popular specimen for mineral collectors.
Geological facts
The purple color comes from irradiation, iron impurities, and the presence of trace elements. It was once considered one of the five cardinal gemstones alongside diamonds and rubies until large deposits were found in Brazil.
Field identification & locations
Identify by its characteristic purple hue and quartz-like hardness (can scratch glass). Found globally, with major deposits in Brazil, Uruguay, Zambia, and South Korea.
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