mineral

Amethyst

Silicon Dioxide with Iron impurities (SiO2)

AI-generated identification · may be incorrect

Hardness: 7 (Mohs scale); Color: Pale lilac to deep purple; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 (Mohs scale)
Color: Pale lilac to deep purple
Luster: Vitreous (glassy)

Identified April 14, 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: Pale lilac to deep purple; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Formation & geological history

Formed in hydrothermal veins or as linings in gas cavities (geodes) within volcanic rocks. The purple color comes from irradiation, iron impurities, and the presence of trace elements. Most deposits are found in Cenozoic or Mesozoic volcanic layers.

Uses & applications

Used extensively in jewelry (faceted gemstones, cabochons), ornamental carvings, and as a popular specimen for mineral collectors and metaphysical practitioners.

Geological facts

Amethyst was considered a 'Cardinal gem' (one of the five most valuable gems) until the 18th century, when large deposits were discovered in Brazil. Its name comes from the Greek 'amethystos', meaning 'not intoxicated', due to a belief it protected the wearer from drunkenness.

Field identification & locations

Identify in the field by its distinct purple color and 6-sided pyramidal terminations. Look for it inside agate-lined geodes or in basaltic cavities. Common locations include Brazil, Uruguay, Zambia, and Ontario, Canada.