mineral

Amethyst

Silicon Dioxide (SiO2) with iron impurities

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

Hardness: 7 on Mohs scale
Color: Purple to violet
Luster: Vitreous (glassy)

Identified March 25, 2026More mineral →

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Physical properties

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

Formation & geological history

Forms in hydrothermal veins or as linings in volcanic geodes. The purple color results from gamma irradiation and trace iron impurities within the quartz lattice. Most commercial specimens range from Cretaceous to Tertiary in age.

Uses & applications

Used primarily in jewelry (rings, necklaces), as decorative geodes, and in metaphysical practices. High-quality specimens are collectors' items, while lower grades are ground for industrial glass or electronics-grade quartz.

Geological facts

Amethyst was considered one of the 'Cardinal gems' until large deposits were found in Brazil. The name comes from the Ancient Greek 'amethystos', meaning 'not intoxicated', as it was believed to prevent drunkenness.

Field identification & locations

Identify by its distinctive purple hue and hexagonal crystal shape if raw. Commonly found in Brazil, Uruguay, Zambia, and South Korea. In the field, look for crystalline cavities within basaltic or volcanic rock formations.

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