mineral

Amethyst

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale), Color: Purple to violet variations, Luster: Vitreous/Glassy, Crystal Structure: Hexagonal (trigonal), Cleavage: None (conchoidal fracture), Specific Gravity: 2.65

Identified February 28, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale), Color: Purple to violet variations, Luster: Vitreous/Glassy, Crystal Structure: Hexagonal (trigonal), Cleavage: None (conchoidal fracture), Specific Gravity: 2.65

Formation & geological history

Forms in volcanic rocks, particularly in geodes or hollow cavities where silica-rich fluids cool and crystallize over millions of years. Its purple color comes from iron impurities and natural irradiation and can date back to various geological eras.

Uses & applications

Primarily used in jewelry (facetted or as cabochons), decorative carvings, and as a popular specimen for mineral collectors and metaphysical practitioners.

Geological facts

Until the 18th century, amethyst was considered one of the 'Cardinal gems' on par with diamond and ruby, until large deposits were found in Brazil. It is the birthstone for February.

Field identification & locations

Identify by its purple hue and hexagonal crystal habit. Found globally with prominent deposits in Brazil, Uruguay, and Zambia. In the field, look for crystalline clusters inside igneous geodes or veins.