mineral

Amethyst

Silicon Dioxide (SiO2) with Iron impurities

Hardness: 7 on Mohs scale; Color: Purple to violet due to iron irradiation; Luster: Vitreous (glassy); Crystal Structure: Hexagonal/Trigonal (often found as druse or terminated pyramids); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.

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

Identified March 16, 2026More mineral →

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Physical properties

Formation & geological history

Formed in hydrothermal veins or as linings inside volcanic geodes (amygdules) when silica-rich water precipitates crystals over millions of years. Common in Cenozoic and Mesozoic basaltic flows.

Uses & applications

Primarily used as a gemstone in jewelry (rings, necklaces), high-end decorative interior design (large geodes), and widely collected as mineral specimens for metaphysical or aesthetic interest.

Geological facts

Until the 18th century, amethyst was considered one of the 'Cardinal Gems' alongside diamond and ruby, but became more common after large deposits were found in Brazil. It is the birthstone for February.

Field identification & locations

Identify by its distinct purple hue and vitreous luster. In the field, look for 'druzy' crystal clusters within hollow rocky nodules (geodes). Major locations include Rio Grande do Sul (Brazil), Artigas (Uruguay), and Ontario (Canada).

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