gemstone

Tumbled amethyst

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

AI-generated identification · may be incorrect

Mohs hardness 7; purple, translucent, vitreous luster, with a hexagonal crystal structure and no distinct cleavage. The stone shown is polished and rounded, so its natural crystal form is not visible.

Identified October 12, 2026More gemstone →

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Physical properties

Formation & geological history

Forms as quartz crystals in gas cavities and veins, often in volcanic rocks; deposits range from ancient to geologically recent. Its purple color develops through trace iron and radiation exposure during formation.

Uses & applications

Used in jewelry, carvings, ornaments, and mineral collections; lower-grade material is commonly tumbled.

Geological facts

Amethyst is the traditional February birthstone. Prolonged heating can alter its color, sometimes producing yellow or green quartz.

Field identification & locations

Identify by its purple color, glassy luster, and hardness; major sources include Brazil, Uruguay, Zambia, and Russia. This small tumbled specimen is commonly worth about $2–$15 USD.