mineral
Amethyst
Quartz (Silicon Dioxide with iron impurities, SiO2)
Hardness: 7 Mohs; Color: Pale to deep purple; Luster: Vitreous; Crystal Structure: Hexagonal (trigonal); Cleavage: Indistinct; Specific Gravity: 2.65
- Hardness
- 7 Mohs
- Color
- Pale to deep purple
- Luster
- Vitreous
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Physical properties
Hardness: 7 Mohs; Color: Pale to deep purple; Luster: Vitreous; Crystal Structure: Hexagonal (trigonal); Cleavage: Indistinct; Specific Gravity: 2.65
Formation & geological history
Formed in hydrothermal veins or geodes when silica-rich water cools. The purple color results from irradiation of trivalent iron (Fe3+) within the quartz structure. Typical ages range from millions to hundreds of millions of years.
Uses & applications
Primarily used as a gemstone in jewelry, for decorative carvings, and as a popular specimen for mineral collectors and metaphysical practitioners.
Geological facts
Amethyst was once considered as valuable as diamonds, rubies, and emeralds until the discovery of large deposits in Brazil in the 19th century. Its name comes from the Ancient Greek word 'amethystos', meaning 'not intoxicated'.
Field identification & locations
Identified by its purple hue and hexagonal crystal habit. Found globally with major deposits in Brazil, Uruguay, Zambia, and Canada. In the field, look for purple crystals inside dacite or basalt cavities (geodes).
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