mineral

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Hardness: 7 (Mohs scale), Color: light to deep purple/lavender, Luster: Vitreous (glassy), Crystal Structure: Trigonal/Hexagonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65

Identified July 4, 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: light to deep purple/lavender, Luster: Vitreous (glassy), Crystal Structure: Trigonal/Hexagonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65

Formation & geological history

Forms in hydrothermal veins or as linings within volcanic rock cavities (geodes). The purple color is caused by irradiation of trivalent iron impurities within the quartz crystal lattice.

Uses & applications

Primarily used in jewelry, as cabochons or faceted stones, and as decorative mineral specimens for collectors and metaphysical use.

Geological facts

Amethyst was considered a precious stone on par with diamonds until large deposits were discovered in Brazil in the 1700s. Its name comes from the Greek 'amethystos', meaning 'not intoxicated'.

Field identification & locations

Identify in the field by its distinct purple color and hexagonal prism crystal habits. Commonly found in Brazil, Uruguay, Zambia, and Ontario. Collectors should look for saturated color and clarity.