mineral

Tumbled amethyst

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

AI-generated identification · may be incorrect

Mohs hardness 7; translucent purple to reddish-violet, vitreous luster, hexagonal crystal structure, and no prominent cleavage. The rounded surface indicates mechanical tumbling and polishing.

Identified September 17, 2026More mineral →

Explore Tumbled amethyst in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Mohs hardness 7; translucent purple to reddish-violet, vitreous luster, hexagonal crystal structure, and no prominent cleavage. The rounded surface indicates mechanical tumbling and polishing.

Formation & geological history

Forms in silica-rich hydrothermal fluids filling volcanic cavities, especially basaltic geodes; many commercial specimens formed in Mesozoic to Cenozoic volcanic rocks. Its purple color develops through trace iron and natural radiation.

Uses & applications

Used as an ornamental stone, jewelry, carvings, beads, and mineral specimens; lower-grade material is widely sold as tumbled stones.

Geological facts

Amethyst is the February birthstone and the most valued quartz variety. Heating can turn it yellow-orange, producing citrine or ametrine-like material.

Field identification & locations

Identify it by its purple color, glassy luster, hardness, and lack of obvious cleavage; it can scratch glass but should not be confused with dyed glass or purple fluorite. Major sources include Brazil, Uruguay, Zambia, and Bolivia.