gemstone

Tumbled amethyst

Quartz, silicon dioxide (SiO₂), purple variety colored mainly by iron impurities and irradiation

AI-generated identification · may be incorrect

Mohs hardness 7; translucent purple with a vitreous luster and conchoidal fracture. Trigonal crystal structure; the pictured piece is polished/tumbled, so cleavage is not apparent; specific gravity is about 2.65.

Identified September 21, 2026More gemstone →

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Physical properties

Formation & geological history

Amethyst forms when iron-bearing quartz crystallizes in volcanic cavities, commonly in basaltic geodes, and later develops its purple color through natural irradiation. Deposits range from Precambrian to Cenozoic age.

Uses & applications

Used for inexpensive jewelry, carvings, ornaments, healing-crystal products, and mineral collections; polished pieces are commonly sold as pocket stones.

Geological facts

Color ranges from pale lilac to deep violet and may fade with prolonged sunlight or heat. Major sources include Brazil, Uruguay, Zambia, Bolivia, and Mexico.

Field identification & locations

Identify it by its glassy luster, hardness, conchoidal fracture, and purple color; it should scratch ordinary glass but not be scratched by a steel knife. The smooth rounded shape indicates human tumbling.