mineral
Amethyst
Amethyst (SiO2 with iron impurities)
Hardness: 7 on Mohs scale; Color: Purple to deep violet; Luster: Vitreous; Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65
- Hardness
- 7 on Mohs scale
- Color
- Purple to deep violet
- Luster
- Vitreous
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Physical properties
Hardness: 7 on Mohs scale; Color: Purple to deep violet; Luster: Vitreous; Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65
Formation & geological history
Formed in hydrothermal veins or as linings in geodes. The purple color is caused by irradiation of iron impurities within the silicon dioxide crystal lattice. Common in volcanic rocks.
Uses & applications
Extensively used in jewelry (faceted or cabochon), as a decorative gemstone, and highly popular among mineral collectors.
Geological facts
Amethyst was considered one of the five cardinal gemstones until large deposits were found in Brazil. Its name comes from the Ancient Greek 'amethystos', meaning 'not intoxicated'.
Field identification & locations
Identify by its distinct purple hue and quartz crystal habit. Commonly found in Brazil, Uruguay, and South Korea. Collectors should look for deep, uniform color and transparency.
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