mineral

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Hardness: 7 on the Mohs scale; Color: Purple, violet, or lavender; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (Trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 on the Mohs scale
Color: Purple, violet, or lavender
Luster: Vitreous (glassy)

Identified March 16, 2026More mineral →

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Physical properties

Hardness: 7 on the Mohs scale; Color: Purple, violet, or lavender; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (Trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Formation & geological history

Formed in hydrothermal veins and volcanic cavities (geodes). The purple color is caused by gamma irradiation of trivalent iron impurities. These can range in age from millions to hundreds of millions of years depending on the host rock.

Uses & applications

Primarily used in jewelry making, ornamental carvings, and as a popular collector's cabinet specimen. It has been used historically in decorative arts and as a gemstone for thousands of years.

Geological facts

The name comes from the Ancient Greek 'amethystos', meaning 'not intoxicated', as it was believed to protect the wearer from drunkenness. It is the birthstone for February and was once considered a 'Cardianal Gem' alongside diamonds and rubies.

Field identification & locations

Identify in the field by its distinct purple hue, glass-like luster, and lack of cleavage (breaks with curved surfaces). Look for it in basaltic or volcanic regions. Common locations include Brazil, Uruguay, and Zambia.

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