mineral

Amethyst

Silicon Dioxide with Iron Impurities (SiO2)

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

Hardness: 7 (Mohs scale)
Color: Purple, violet, or lavender
Luster: Vitreous (glassy)

Identified July 6, 2026More mineral →

Explore Amethyst in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness: 7 (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 igneous or metamorphic environments, typically inside volcanic geodes. The purple color is caused by irradiation of trivalent iron (Fe3+) in the quartz structure. Most specimens are from the Mesozoic or Cenozoic eras.

Uses & applications

Primarily used as a gemstone in jewelry, for decorative carvings, and by crystal collectors for aesthetic and metaphysical purposes.

Geological facts

Amethyst was considered a precious stone comparable to diamond until large deposits were found in Brazil in the 1700s. Its name comes from the Ancient Greek word 'amethystos', meaning 'not intoxicated', as it was believed to prevent drunkenness.

Field identification & locations

Identify by its characteristic purple color and quartz-like hardness. Often found in geode formations in Brazil, Uruguay, Zambia, and South Korea. Look for hexagonal crystal faces and transparency transitions from dark to light.