mineral

Amethyst

Purple quartz (SiO₂), colored mainly by iron impurities and irradiation

AI-generated identification · may be incorrect

Mohs hardness 7; translucent purple to violet, with vitreous luster and conchoidal fracture. Quartz is trigonal and lacks cleavage; the specimen appears rough, fractured, or lightly polished.

Identified September 12, 2026More mineral →

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Physical properties

Mohs hardness 7; translucent purple to violet, with vitreous luster and conchoidal fracture. Quartz is trigonal and lacks cleavage; the specimen appears rough, fractured, or lightly polished.

Formation & geological history

Forms when iron-bearing quartz crystallizes in volcanic cavities, especially basaltic geodes, from hydrothermal fluids. Most deposits formed during the Cenozoic to Precambrian, depending on locality.

Uses & applications

Used as a gemstone, ornamental stone, and mineral specimen; also popular in jewelry and carvings. This small rough piece has modest commercial value.

Geological facts

Amethyst is the purple variety of quartz and can fade with prolonged heat or intense sunlight. Its color ranges from pale lilac to deep “Siberian” violet.

Field identification & locations

Identify it by purple color, glassy luster, hardness sufficient to scratch ordinary glass, and lack of cleavage; glass or fluorite may imitate it. Common sources include Brazil, Uruguay, Zambia, Namibia, and the United States.