mineral

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Hardness: 7 on Mohs scale; Color: Purple to violet; Luster: Vitreous/Glassy; Crystal structure: Trigonal (hexagonal prisms); Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Hardness: 7 on Mohs scale
Color: Purple to violet
Luster: Vitreous/Glassy

Identified March 22, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Purple to violet; Luster: Vitreous/Glassy; Crystal structure: Trigonal (hexagonal prisms); Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Formation & geological history

Formed in hydrothermal veins and igneous rock cavities (geodes) when silica-rich water precipitates. The purple color comes from irradiation of iron impurities in the quartz structure over millions of years.

Uses & applications

Primary use is in jewelry, lapidary arts, and as a collector's mineral. In industry, quartz is used for abrasive and frequency-control applications, though amethyst is usually reserved for decorative purposes.

Geological facts

Until the 18th century, amethyst was considered one of the 'cardinal gems' together with diamond, sapphire, ruby, and emerald. Ancient Greeks believed it could prevent intoxication.

Field identification & locations

Identify in the field by its distinct purple color and 6-sided crystal shape. Commonly found in Brazil, Uruguay, Zambia, and Ontario. Collectors look for deep saturation ('Deep Siberian' purple) and transparency.

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