mineral

Amethyst

Amethyst (Silicon Dioxide, SiO2 with Iron impurities)

Hardness: 7 (Mohs scale), Color: Pale violet to deep purple, Luster: Vitreous/Glassy, Crystal Structure: Trigonal/Hexagonal, Cleavage: None/Conchoidal fracture, Specific Gravity: 2.65

Identified June 18, 2026More mineral →

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 violet to deep purple, Luster: Vitreous/Glassy, Crystal Structure: Trigonal/Hexagonal, Cleavage: None/Conchoidal fracture, Specific Gravity: 2.65

Formation & geological history

Formed in hydrothermal veins or inside volcanic geodes when silica-rich water cools. The purple color is caused by irradiation of trivalent iron (Fe3+) impurities. Most specimens are from the Cretaceous period in basaltic flows.

Uses & applications

Primarily used as a gemstone in jewelry (birthstone for February), decorative ornaments, and highly valued by mineral collectors and metaphysical practitioners.

Geological facts

Amethyst was considered a Cardinal Gem until the 18th century, ranked alongside diamonds and rubies in value. Its name comes from the Greek 'amethystos', meaning 'not intoxicated', as it was once believed to prevent drunkenness.

Field identification & locations

Identify by its characteristic purple terminal crystal points and hardness that scratches glass. Common locations include the Rio Grande do Sul region of Brazil, Uruguay, and Thunder Bay, Ontario.

Other mineral specimens

See all

Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Schist

Metamorphic

Epidote

Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)

metamorphic

Nephrite Jade

Nephrite

Mineral/Rock

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety often found as a river rock)

Metamorphic Rock

Green Apatite on Albite

Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]

mineral