mineral
Amethyst
Silicon Dioxide (SiO2) with iron impurities
Hardness: 7 on Mohs scale; Color: Purple, violet, or lavender; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.
- Hardness
- 7 on Mohs scale
- Color
- Purple, violet, or lavender
- Luster
- Vitreous (glassy)
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Physical properties
Hardness: 7 on Mohs scale; Color: Purple, violet, or lavender; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.
Formation & geological history
Forms in hydrothermal veins and basaltic geodes. The purple color is caused by gamma irradiation of trivalent iron impurities and the presence of trace elements. Found in geological environments ranging from recent volcanic deposits to ancient metamorphic rocks.
Uses & applications
Primarily used in jewelry, as decorative display specimens, and in spiritual/healing practices. It is the birthstone for February.
Geological facts
Amethyst was as valuable as diamonds until the 18th century when large deposits were found in Brazil. The name comes from the Ancient Greek 'amethystos', meaning 'not intoxicated', as it was believed to protect the wearer from drunkenness.
Field identification & locations
Identify by its distinctive purple hue and hexagonal crystal form if raw. In tumbled form, it shows white cloudy inclusions (chevron patterns) or internal fractures. Commonly found in Brazil, Uruguay, Zambia, and South Korea.
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