mineral

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Hardness: 7 on Mohs scale; Color: light to deep purple; Luster: Vitreous (glassy); Crystal structure: Hexagonal/Trigonal; Cleavage: None (Conchoidal fracture); Specific gravity: 2.65

Hardness: 7 on Mohs scale
Color: light to deep purple
Luster: Vitreous (glassy)

Identified April 29, 2026More mineral →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness: 7 on Mohs scale; Color: light to deep purple; Luster: Vitreous (glassy); Crystal structure: Hexagonal/Trigonal; Cleavage: None (Conchoidal fracture); Specific gravity: 2.65

Formation & geological history

Forms inside igneous volcanic rocks (geodes) or hydrothermal veins when silica-rich water crystallizes over time. The purple color is caused by trace amounts of iron radiated by natural radioactivity in the surrounding rock.

Uses & applications

Primarily used in jewelry, lapidary arts, and as a popular collector's mineral. High-quality specimens are faceted into gemstones.

Geological facts

Amethyst is the birthstone for February. Its name comes from the Greek word 'amethystos', meaning 'not intoxicated', as ancient Greeks believed the stone could prevent drunkenness.

Field identification & locations

Identify by its purple hue, 6-sided crystal habit (if points are present), and its ability to scratch glass. Commonly found in Brazil, Uruguay, Zambia, and Ontario, Canada.

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