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 29, 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

Formed in hydrothermal veins and basaltic cavities (vugs/geodes). The purple color is caused by irradiation of trivalent iron impurities within the quartz crystal structure. They occur in deposits of various geological ages, often in volcanic rocks.

Uses & applications

Primarily used in jewelry (faceting and cabochons), as decorative specimens for interiors, and increasingly in metaphysical or collector markets.

Geological facts

Until the 18th century, amethyst was included in the cardinal gemstones alongside diamond, ruby, emerald, and sapphire. Large deposits found in Brazil lowered its market value, but deep purple 'Siberian' quality remains highly prized.

Field identification & locations

Identify by its characteristic purple hue and inability to be scratched by a steel knife. Common locations include Brazil, Uruguay, Zambia, and South Korea. Collectors should look for even color distribution and lack of inclusions.

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