mineral
Amethyst
Amethyst (Silicon Dioxide with iron impurities), SiO2
Hardness: 7 on Mohs scale; Color: Purple to violet; Luster: Vitreous (glass-like); Crystal structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65
- Hardness
- 7 on Mohs scale
- Color
- Purple to violet
- Luster
- Vitreous (glass-like)
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Physical properties
Hardness: 7 on Mohs scale; Color: Purple to violet; Luster: Vitreous (glass-like); Crystal structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65
Formation & geological history
Formed in hydrothermal veins or geodes within igneous rocks (primarily basalt) when silica-rich water cools. The purple color is caused by trace amounts of iron and natural irradiation over millions of years.
Uses & applications
Primary use is in jewelry (faceted gemstones, beads) and as decorative specimens or metaphysical stones. It is the birthstone for February.
Geological facts
Ancient Greeks believed amethyst could prevent intoxication. The name comes from the Greek word 'amethystos', meaning 'not drunk'. Heat treating amethyst can change its color to yellow-orange, creating 'citrine'.
Field identification & locations
Identify in the field by its distinct purple hue and quartz-like crystal habit. Commonly found in Brazil, Uruguay, Zambia, and South Korea. Collectors should look for deep, uniform color (Siberian quality) and high transparency.
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