mineral
Amethyst Quartz
Silicon Dioxide (SiO2) with iron impurities
Hardness: 7 on the Mohs scale. Color: Pale lilac to deep purple. Luster: Vitreous (glassy). Crystal Structure: Hexagonal (trigonal). Cleavage: None (conchoidal fracture). Specific Gravity: 2.65.
- Hardness
- 7 on the Mohs scale
- Color
- Pale lilac to deep purple
- Luster
- Vitreous (glassy)
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Physical properties
Hardness: 7 on the Mohs scale. Color: Pale lilac 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 cavities within hollow igneous rocks (geodes). The purple color is caused by irradiation of trivalent iron impurities within the quartz crystal lattice.
Uses & applications
Primarily used as a semi-precious gemstone in jewelry, for decorative carvings, and as a popular specimen for mineral collectors.
Geological facts
Amethyst was considered a cardinal gem until the 18th century. The name comes from the Ancient Greek 'amethystos', meaning 'not intoxicated', expressing the belief that the stone protected its owner from drunkenness.
Field identification & locations
Identify by its characteristic purple zoning, hexagonal crystal habit, and ability to scratch glass. Common locations include Brazil, Uruguay, Zambia, and South Korea.
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