mineral

Amethyst

Amethyst (SiO2 - Silicon Dioxide with Iron impurities)

Hardness: 7 on Mohs scale; Color: Purple, violet, or lavender; Luster: Vitreous (glassy); Crystal structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Hardness: 7 on Mohs scale
Color: Purple, violet, or lavender
Luster: Vitreous (glassy)

Identified March 7, 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: Purple, violet, or lavender; Luster: Vitreous (glassy); Crystal structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Formation & geological history

Formed in hydrothermal veins or volcanic geodes where silica-rich water cools and crystallizes at low temperatures. The purple hue is caused by irradiation of trivalent iron impurities (Fe3+) in the quartz structure.

Uses & applications

Primarily used in jewelry (faceting, cabochons), carvings, and as a popular decorative collectors' specimen. Also used in metaphysical and holistic practices.

Geological facts

Until the 18th century, amethyst was included in the cardinal gemstones alongside diamond, ruby, emerald, and sapphire. Large deposits found in Brazil later reduced its rarity and market value. It is the birthstone for February.

Field identification & locations

Identify by its distinct purple color and 6-sided crystal habit. In the field, look for hexagonal points often emerging from a white quartz or gray agate base. Often found in basaltic rocks or pegmatites. Significant locations include Brazil, Uruguay, and Canada.

Other mineral specimens

See all

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)]

mineral

Epidote

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

mineral