mineral

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Hardness: 7 (Mohs scale), Color: light to deep purple, Luster: vitreous (glassy), Crystal System: Trigonal (Hexagonal trapezohedral), Cleavage: None (conchoidal fracture), SG: 2.65

Identified June 19, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale), Color: light to deep purple, Luster: vitreous (glassy), Crystal System: Trigonal (Hexagonal trapezohedral), Cleavage: None (conchoidal fracture), SG: 2.65

Formation & geological history

Formed in hydrothermal veins or as linings in geodes. The purple color is caused by trace amounts of iron (⁃Fe4+) being irradiated within the quartz crystal lattice. Found in volcanic basalt and sedimentary deposits.

Uses & applications

Primarily used as a semi-precious gemstone in jewelry (rings, necklaces), as decorative omamental pieces, and highly valued by collectors. It is also the traditional birthstone for February.

Geological facts

Until the 18th century, amethyst was included in the cardinal gemstones, ranked alongside diamonds and rubies. The name comes from the Ancient Greek 'amethystos', meaning 'not intoxicated', as it was believed to prevent drunkenness.

Field identification & locations

Identify by its distinctive purple hue and lack of cleavage; it will scratch glass but cannot be scratched by a steel pocket knife. Commonly found in Brazil, Uruguay, and South Korea.

Other mineral specimens

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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