gemstone

Tumbled amethyst

Quartz, SiO₂; purple variety colored mainly by iron impurities and irradiation

AI-generated identification · may be incorrect

Mohs hardness 7; translucent purple to violet with a pale quartz tip, vitreous luster, and no visible cleavage. Hexagonal crystal structure, though tumbling has rounded the specimen; specific gravity about 2.65.

Identified August 11, 2026More gemstone →

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Physical properties

Formation & geological history

Forms when silica-rich hydrothermal fluids fill cavities in volcanic rocks, especially basaltic lava flows; color develops during growth and later irradiation. Most specimens formed in relatively young volcanic environments, commonly Cretaceous to Cenozoic.

Uses & applications

Used as a low-cost gemstone, jewelry, carvings, polished specimens, and metaphysical décor; large geodes are also collectible.

Geological facts

Amethyst is the birthstone for February and was historically valued nearly as highly as ruby until large Brazilian deposits were discovered.

Field identification & locations

Identify by its purple quartz appearance, glassy luster, hardness, and lack of strong cleavage; common sources include Brazil, Uruguay, Zambia, and Madagascar. A scratch test should be avoided on valuable pieces.