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 25, 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 or geodes when silica-rich water flows through rock cavities. Its purple color comes from irradiation of iron impurities over millions of years. Can be found in rocks from the Precambrian to Cenozoic eras.

Uses & applications

Primary use is in jewelry (faceted gemstones, beads, and cabochons). It is also highly popular for mineral collecting, lapidary art, and in the 'healing crystal' market.

Geological facts

Until the discovery of large deposits in Brazil in the 19th century, amethyst was considered one of the 'cardinal gems' alongside diamond and ruby. Its name comes from the Greek 'amethystos', meaning 'not intoxicated', as it was believed to prevent drunkenness.

Field identification & locations

Identify in the field by its distinct purple hue and crystal habit (six-sided prisms). It will scratch glass but cannot be scratched by a steel knife. Common locations include Brazil, Uruguay, Zambia, and Arizona, USA.

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