mineral
Amethyst on Matrix
Amethyst (Silicon Dioxide, SiO2) with impurities of iron and irradiation
Hardness: 7 on Mohs scale. Color: Pale to deep purple. Luster: Vitreous/glassy. Crystal structure: Hexagonal (trigonal). Cleavage: None (conchoidal fracture). Specific gravity: 2.65.
- Hardness
- 7 on Mohs scale
- Color
- Pale to deep purple
- Luster
- Vitreous/glassy
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Physical properties
Hardness: 7 on Mohs scale. Color: Pale to deep purple. Luster: Vitreous/glassy. Crystal structure: Hexagonal (trigonal). Cleavage: None (conchoidal fracture). Specific gravity: 2.65.
Formation & geological history
Formed in hydrothermal veins or as linings in geodes within volcanic rocks where silica-rich fluids crystallized over millions of years. The purple color is caused by trace amounts of iron influenced by natural radiation.
Uses & applications
Primarily used in jewelry, as decorative display specimens, and in metaphysical collecting. Industrial high-quality quartz (though rarely amethyst specifically) is used in electronics.
Geological facts
Amethyst was considered a 'Cardinal Gem' until the 18th century, ranked alongside diamonds and rubies, until large deposits were found in Brazil. The name comes from the Ancient Greek word 'amethystos', meaning 'not intoxicated'.
Field identification & locations
Identify in the field by its purple hue and hexagonal crystal habit. Common locations include Brazil, Uruguay, Zambia, and South Korea. Look for purple crystals inside vugs or cavities in basaltic rocks.
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