gemstone

Tumbled amethyst

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

AI-generated identification · may be incorrect

Typically Mohs hardness 7, vitreous to waxy luster, white-to-purple color zoning, and translucent massive or crystalline quartz; cleavage is absent, with conchoidal fracture. The specimen appears polished/tumbled and may include cloudy quartz or iron staining.

Identified September 9, 2026More gemstone →

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

Formation & geological history

Forms chiefly in cavities and veins of volcanic rocks, especially basalt, where silica-rich fluids deposited quartz over geologic time, commonly during the Cenozoic or older events. Purple color develops from trace iron and natural radiation.

Uses & applications

Used for beads, carvings, cabochons, display specimens, and ornamental objects; gem-quality crystals are used in jewelry. Common tumbled pieces have modest commercial value.

Geological facts

Amethyst is the purple variety of quartz and is February’s birthstone. Heating can turn it yellow-orange, producing citrine-like material.

Field identification & locations

Identify by its purple quartz appearance, glassy luster, hardness, and lack of cleavage; it should scratch glass but not be easily scratched by a steel knife. Major sources include Brazil, Uruguay, Zambia, and Namibia.