mineral
Amethyst
Silicon Dioxide (SiO2) with trace Iron impurities
Hardness: 7 Mohs; Color: Purple, violet, or lavender; Luster: Vitreous (glassy) when polished; Crystal Structure: Hexagonal/Trigonal; Specific Gravity: 2.65
- Hardness
- 7 Mohs
- Color
- Purple, violet, or lavender
- Luster
- Vitreous (glassy) when polished
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Physical properties
Hardness: 7 Mohs; Color: Purple, violet, or lavender; Luster: Vitreous (glassy) when polished; Crystal Structure: Hexagonal/Trigonal; Specific Gravity: 2.65
Formation & geological history
Formed in hydrothermal veins or cavities (geodes) within igneous rocks, typically from silica-rich water during the late stages of volcanic activity. Color comes from irradiation of iron impurities.
Uses & applications
Widely used for jewelry, lapidary arts, metaphysical practices, and as a popular decorative collectors' specimen.
Geological facts
Amethyst was considered a 'Cardinal gem' alongside diamond and ruby until large deposits were found in Brazil. Its name comes from the Greek word 'amethystos', meaning 'not intoxicated'.
Field identification & locations
Identified by its distinctive purple hue and lack of cleavage. Common in Brazil, Uruguay, and Zambia. Tumbled specimens like this one are smoothed in a rotating drum with abrasives.
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