mineral
Amethyst
Amethyst (Silicon Dioxide - SiO2)
Hardness: 7 (Mohs scale); Color: Purple, violet; Luster: Vitreous (glassy); Crystal structure: Trigonal/Hexagonal; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65
- Hardness
- 7 (Mohs scale)
- Color
- Purple, violet
- Luster
- Vitreous (glassy)
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Physical properties
Hardness: 7 (Mohs scale); Color: Purple, violet; Luster: Vitreous (glassy); Crystal structure: Trigonal/Hexagonal; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65
Formation & geological history
Formed within volcanic rocks (basalts and rhyolites) from hydrothermal solutions as geothermal water cools and precipitates silica. The purple color comes from irradiation of iron impurities.
Uses & applications
Predominantly used as a gemstone for jewelry, in spiritual practices (metaphysical uses), and as decorative cabinet specimens for collectors.
Geological facts
Amethyst was considered a precious stone on par with Diamond and Ruby until large deposits were found in Brazil. Its name comes from the Ancient Greek 'amethystos', meaning 'not intoxicated'.
Field identification & locations
Identify by its characteristic purple color and hexagonal crystal points (if uncut). Found globally, notably in Brazil, Uruguay, and North America. It is the birthstone for February.
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