mineral

Amethyst

Silicon Dioxide (SiO2) with iron impurities

AI-generated identification · may be incorrect

Hardness: 7 (Mohs scale), Color: Purple to deep violet, Luster: Vitreous/glassy, Crystal structure: Trigonal (hexagonal prisms), Cleavage: None (conchoidal fracture), Specific Gravity: 2.65

Identified June 1, 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 to deep violet, Luster: Vitreous/glassy, Crystal structure: Trigonal (hexagonal prisms), Cleavage: None (conchoidal fracture), Specific Gravity: 2.65

Formation & geological history

Forms in hydrothermal veins or as linings in geodes within igneous volcanic rocks when silica-rich water precipitates in gas cavities (amygdales). Purple color comes from iron irradiation.

Uses & applications

Highly popular in jewelry including rings and necklaces, used in home decor, and widely collected by mineral enthusiasts for aesthetic and metaphysical properties.

Geological facts

Until the 18th century, amethyst was included in the cardinal gemstones alongside diamond, ruby, emerald, and sapphire. Its name comes from the Greek 'amethystos', meaning 'not intoxicated'.

Field identification & locations

Look for its characteristic purple color and hexagonal prism shape. Commonly found in Brazil, Uruguay, South Korea, and the United States (Arizona/North Carolina). It can reach deep violet shades when irradiated naturally.