mineral

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Hardness: 7 on Mohs scale; Color: Purple, violet, or lavender; Luster: Vitreous (glass-like); Crystal Structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: Purple, violet, or lavender
Luster: Vitreous (glass-like)

Identified March 24, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Purple, violet, or lavender; Luster: Vitreous (glass-like); Crystal Structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Formation & geological history

Formed in hydrothermal veins or as linings within volcanic rock cavities (geodes). The purple color results from irradiation of trivalent iron (Fe3+) in the quartz structure. Most specimens range from late Mesozoic to Cenozoic eras.

Uses & applications

Primarily used as a gemstone in jewelry, decorative carvings, and as a popular collector's mineral. Occasionally used in industrial applications requiring high-purity quartz.

Geological facts

Amethyst was considered a 'Cardinal Gem' until the discovery of large deposits in Brazil in the 19th century. The name comes from the Greek 'amethystos,' meaning 'not intoxicated,' as Ancient Greeks believed it prevented drunkenness.

Field identification & locations

Identify in the field by its hexagonal crystal habit, purple hue, and inability to be scratched by a steel pocketknife. Common locations include Brazil, Uruguay, Zambia, and Ontario, Canada.

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