mineral
Amethyst
Silicon Dioxide (SiO2) with iron impurities
Hardness: 7 on Mohs scale; Color: Pale lavender 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 lavender to deep purple
- Luster
- Vitreous (glassy)
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Physical properties
Hardness: 7 on Mohs scale; Color: Pale lavender to deep purple; Luster: Vitreous (glassy); Crystal Structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65
Formation & geological history
Forms in geothermal environments, typically within volcanic rock cavities (geodes) when silica-rich water precipitates crystals over millions of years. The purple color is caused by irradiation of iron impurities.
Uses & applications
Widely used in jewelry (rings, necklaces), as decorative display pieces, and in spiritual/healing stone collections.
Geological facts
Until the 18th century, amethyst was considered one of the five cardinal gemstones alongside diamond, ruby, emerald, and sapphire, until large deposits were found in Brazil.
Field identification & locations
Look for a purple hue, a glassy luster, and the ability to scratch glass. Commonly found in Brazil, Uruguay, Zambia, and South Korea. Collectors should look for deep saturation and clarity.
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