mineral

Amethyst

Silicon dioxide (SiO2) with iron impurities

Hardness: 7 on Mohs scale; Color: Purple, violet, to deep reddish-purple; Luster: Vitreous; Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: Purple, violet, to deep reddish-purple
Luster: Vitreous

Identified January 23, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Purple, violet, to deep reddish-purple; Luster: Vitreous; Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Formation & geological history

Formed in hydrothermal veins and gas cavities (geodes) within volcanic rocks. The purple color is caused by irradiation of trivalent iron (Fe3+) impurities. They are found in rocks of various geological ages, often Cretaceous to present.

Uses & applications

Primarily used as a gemstone in jewelry (rings, bracelets, necklaces), as decorative specimens for mineral collectors, and in alternative medicine/metaphysics.

Geological facts

Amethyst was considered a 'Precious Stone' until large deposits were found in Brazil. The name comes from the Greek 'amethystos', meaning 'not intoxicated', as it was once believed to prevent drunkenness.

Field identification & locations

Identify by its characteristic purple color and ability to scratch glass (hardness 7). In the field, look for purple crystals inside hollow amygdaloidal basalt or geodes. Major deposits are found in Brazil, Uruguay, Zambia, and Ontario.

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