mineral
Amethyst
Silicon Dioxide (SiO2) with trace Iron (Fe3+)
Hardness: 7 on Mohs scale; Color: Purple to deep violet; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65
- Hardness
- 7 on Mohs scale
- Color
- Purple to deep violet
- Luster
- Vitreous (glassy)
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Physical properties
Hardness: 7 on Mohs scale; Color: Purple to deep violet; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65
Formation & geological history
Formed in hydrothermal veins or inside volcanic geodes when silica-rich fluids cool and crystallize in the presence of iron trace elements and natural irradiation. Found in basaltic lava flows and granite pegmatites.
Uses & applications
Extensively used in jewelry (faceting and cabochons), carvings, metaphysical decor, and as popular mineral specimens for collectors.
Geological facts
The purple color is caused by the replacement of silicon by iron in the crystal lattice, followed by exposure to natural ionizing radiation. It was as valuable as diamond until large deposits were discovered in Brazil in the 19th century.
Field identification & locations
Identify by its characteristic purple terminal crystal faces and hexagonal cross-sections. Commonly found in Brazil, Uruguay, Zambia, and South Korea. Collectors look for deep saturation and clarity.
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