mineral

Amethyst

Silicon Dioxide with Iron impurities (SiO2)

Hardness: 7 on Mohs scale; Color: Variations of purple, violet, and lavender; Luster: Vitreous (glass-like); Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: Variations of purple, violet, and lavender
Luster: Vitreous (glass-like)

Identified March 11, 2026More mineral →

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Physical properties

Formation & geological history

Formed in hydrothermal veins and hollow cavities (geodes) within volcanic rocks. The purple color is caused by gamma irradiation of trivalent iron impurities within the quartz structure. Most specimens found today are from the Cretaceous or Tertiary periods.

Uses & applications

Predominantly used as a gemstone in jewelry (rings, necklaces), as decorative ornamental pieces, and is highly sought after by mineral collectors for its metaphysical associations and aesthetic beauty.

Geological facts

Until the 18th century, amethyst was included in the cardinal gemstones, considered as valuable as diamond or ruby. The largest deposits are currently found in Brazil and Uruguay.

Field identification & locations

Identify by its distinct purple color, inability to be scratched by a steel knife, and glass-like surface. Found globally, with major mines in Rio Grande do Sul (Brazil), Artigas (Uruguay), and parts of Arizona and Ontario.

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