mineral

Amethyst

SiO2 (Silicon Dioxide with Iron impurities)

Hardness: 7 on Mohs scale; Color: Purple, violet, or lavender; Luster: Vitreous/glassy; Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific gravity: 2.65.

Hardness: 7 on Mohs scale
Color: Purple, violet, or lavender
Luster: Vitreous/glassy

Identified May 30, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Purple, violet, or lavender; Luster: Vitreous/glassy; Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific gravity: 2.65.

Formation & geological history

Formed in hydrothermal veins or cavities (geodes) within volcanic rocks when silica-rich water precipitates crystals. The purple color is caused by irradiation of trivalent iron impurities. Most commercial specimens are from the Cretaceous period formations.

Uses & applications

Extensively used in jewelry (faceting and cabochons), as decorative display specimens, and in spiritual/metaphysical practices.

Geological facts

Amethyst was considered a Cardinal Gem (one of the five most precious) until large deposits were found in Brazil in the 1700s. The name comes from the Greek word 'amethystos', meaning 'not intoxicated'.

Field identification & locations

Identified by its purple color and hexagonal crystal terminations. Commonly found in Brazil, Uruguay, and Zambia. In the field, look for volcanic basalt host rock potentially containing vugs or geode structures.