mineral

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Hardness: 7 on Mohs scale; Color: Purple, violet, to deep reddish-purple; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: Purple, violet, to deep reddish-purple
Luster: Vitreous (glassy)

Identified March 30, 2026More mineral →

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Physical properties

Formation & geological history

Formed in igneous or metamorphic environments, primarily within hydrothermal veins or gas cavities (geodes) in volcanic rocks. The purple color is caused by natural irradiation of trace amounts of trivalent iron (Fe3+).

Uses & applications

Predominantly used as a gemstone in jewelry (rings, necklaces, earrings) and as a popular decorative specimen for collectors and metaphysical practitioners.

Geological facts

Amethyst is the birthstone for February. Its name comes from the Ancient Greek 'amethystos', meaning 'not intoxicated', as it was historically believed to protect its owner from drunkenness.

Field identification & locations

Identified by its purple hexagonal prismatic crystals with pyramidal terminations. Commonly found in Brazil, Uruguay, South Korea, Russia, and the United States (Arizona). To identify in the field, look for vitreous purple crystals that can scratch glass but cannot be scratched by a steel pocketknife.

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Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

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)]

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Epidote

Epidote - Ca2(Al2,Fe3+)3(SiO4)3(OH)

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