mineral

Amethyst

Quartz (SiO2) with iron impurities

Hardness: 7 (Mohs scale); Color: pale to deep purple; Luster: vitreous; Crystal structure: hexagonal (trigonal); Cleavage: none (conchoidal fracture); Specific gravity: 2.65

Hardness: 7 (Mohs scale)
Color: pale to deep purple
Luster: vitreous

Identified July 20, 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 to deep purple; Luster: vitreous; Crystal structure: hexagonal (trigonal); Cleavage: none (conchoidal fracture); Specific gravity: 2.65

Formation & geological history

Formed in hydrothermal veins or geodes when silica-rich fluids crystallize in cavities of igneous or metamorphic rocks. The purple color is caused by trace amounts of iron and natural irradiation.

Uses & applications

Widely used for jewelry, lapidary carvings, and as decorative display specimens for collectors and crystal enthusiasts.

Geological facts

Amethyst was once considered one of the five cardinal gemstones alongside diamonds and rubies until large deposits were found in Brazil. Its name comes from the Greek 'amethystos', meaning 'not intoxicated'.

Field identification & locations

Identified by its purple color, crystal habit, and hardness. Commonly found in Brazil, Uruguay, Zambia, and South Korea. Look for hexagonal crystal points and absence of cleavage in the field.