mineral

Amethyst

Silicon Dioxide (SiO2) with trivalent iron (Fe3+) impurities

Hardness: 7.0 Mohs; Color: Deep purple to pale lavender; Luster: Vitreous (glass-like); Crystal Structure: Hexagonal (trigonal); Cleavage: Indistinct; Specific Gravity: 2.65

Hardness: 7
Color: Deep purple to pale lavender
Luster: Vitreous (glass-like)

Identified March 25, 2026More mineral →

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Physical properties

Hardness: 7.0 Mohs; Color: Deep purple to pale lavender; Luster: Vitreous (glass-like); Crystal Structure: Hexagonal (trigonal); Cleavage: Indistinct; Specific Gravity: 2.65

Formation & geological history

Formed in hydrothermal veins and basaltic geodes. The purple color is caused by irradiation of iron impurities within the quartz structure. It can be found in rocks from various geological eras, notably the Cretaceous era in South American deposits.

Uses & applications

Primary use is in jewelry (faceted gemstones and beads) and as ornamental decorative pieces (geodes and spheres). Highly popular for crystal collecting and metaphysical purposes.

Geological facts

Until the discovery of large deposits in Brazil in the 19th century, amethyst was considered one of the 'Cardinal Gems' along with diamond, ruby, sapphire, and emerald. In ancient Greece, it was believed to prevent intoxication.

Field identification & locations

Identify by its characteristic purple color and hexagonal prism growth. In the field, look for quartz-lined cavities in volcanic rocks. Commonly found in Brazil, Uruguay, Zambia, and Ontario, Canada.

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