mineral
Amethyst
SiO2 (Silicon Dioxide with Iron impurities)
Hardness: 7 on Mohs scale; Color: Purple, violet, or lavender; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Specific Gravity: 2.65.
- Hardness
- 7 on Mohs scale
- Color
- Purple, violet, or lavender
- Luster
- Vitreous (glassy)
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Physical properties
Hardness: 7 on Mohs scale; Color: Purple, violet, or lavender; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Specific Gravity: 2.65.
Formation & geological history
Forms in igneous geodes or hydrothermal veins when silica-rich water deposits crystals inside cavities. The purple color comes from irradiation of iron impurities.
Uses & applications
Primarily used in jewelry (faceting or cabochons), decor, and as a popular collector specimen. Historically believed to prevent intoxication.
Geological facts
Amethyst was considered one of the five cardinal gemstones until large deposits were found in Brazil in the 1700s, making it more accessible.
Field identification & locations
Look for its signature purple color and hexagonal prism shapes in raw forms. Tumbled stones like this one show a smooth surface and characteristic transparency. Common locations include Brazil, Uruguay, and Zambia.
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