mineral
Amethyst
Silicon dioxide (SiO2) with iron impurities
Hardness: 7 on Mohs scale; Color: Pale lilac to deep purple; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (rhombohedral); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65
- Hardness
- 7 on Mohs scale
- Color
- Pale lilac to deep purple
- Luster
- Vitreous (glassy)
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Physical properties
Hardness: 7 on Mohs scale; Color: Pale lilac to deep purple; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (rhombohedral); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65
Formation & geological history
Formed in hydrothermal veins or as linings inside volcanic geodes. The purple color comes from irradiation of iron impurities within the quartz structure. Most specimens are from the Cretaceous period.
Uses & applications
Extensively used in jewelry (faceting, cabochons, beads), decorative home decor, and spiritual/metaphysical collections.
Geological facts
Until the 18th century, amethyst was considered one of the five cardinal gemstones alongside diamond, ruby, emerald, and sapphire, before large deposits were found in Brazil.
Field identification & locations
Identify by its purple color, crystal habit, and hardness (it will scratch glass). Commonly found in Brazil, Uruguay, Zambia, and South Korea. Collectors look for deep saturation and clarity.
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