mineral

Amethyst

Silicon Dioxide with iron impurities (SiO2)

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

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

Identified June 11, 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: Pale violet to deep purple; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: None; Specific Gravity: 2.65

Formation & geological history

Formed in hydrothermal veins and hollow rocks (geodes) when silica-rich water cools. The purple color is caused by irradiation of iron impurities within the quartz lattice.

Uses & applications

Primarily used in jewelry (rings, necklaces, earrings), as a collector's gemstone, and in spiritual/decorative items like geodes.

Geological facts

Amethyst was considered a precious stone on par with Diamond until large deposits were found in Brazil. Its name comes from the Ancient Greek 'amethystos', meaning 'not intoxicated'.

Field identification & locations

Identified by its purple hue, inability to be scratched by a steel knife, and lack of cleavage. Commonly found in Brazil, Uruguay, and Zambia. In the field, look for purple crystals inside rocky volcanic geodes.

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

Biotite Schist

Biotite-rich Schist [K(Mg,Fe)3AlSi3O10(F,OH)2]

metamorphic