gemstone
Amethyst
Silicon Dioxide (SiO2) with iron impurities
Hardness: 7 (Mohs), Color: Purple to violet, Luster: Vitreous (glassy), Crystal system: Trigonal/Hexagonal, Refractive index: 1.54-1.55
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Physical properties
Hardness: 7 (Mohs), Color: Purple to violet, Luster: Vitreous (glassy), Crystal system: Trigonal/Hexagonal, Refractive index: 1.54-1.55
Formation & geological history
Forms in hydrothermal veins and basaltic geodes through volcanic activity. The purple color comes from irradiation of iron impurities within the quartz lattice during formation.
Uses & applications
Primarily used in jewelry (faceting, cabochons), as decorative specimens for collectors, and in alternative healing practices.
Geological facts
The color of amethyst can fade if exposed to prolonged sunlight. Historically, ancient Greeks believed amethyst could prevent intoxication.
Field identification & locations
Identify by its distinctive purple hue and hexagonal crystal symmetry if raw. As a cut gem, check for typical 'color zoning' (uneven color distribution) under magnification. Commonly found in Brazil, Uruguay, and Zambia.
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