mineral

Tumbled amethyst

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

AI-generated identification · may be incorrect

Mohs hardness 7; translucent violet-purple color; vitreous luster; hexagonal crystal structure in natural crystals; conchoidal fracture and no cleavage. The smooth surface indicates mechanical tumbling and polishing.

Identified September 8, 2026More mineral →

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Physical properties

Formation & geological history

Forms in cavities of volcanic rocks, especially basaltic lava, when silica-rich hydrothermal fluids deposit quartz and amethyst over geologic time, commonly in Permian to Cenozoic formations.

Uses & applications

Used as an ornamental stone, jewelry, cabochons, carvings, and inexpensive metaphysical or display specimens.

Geological facts

Amethyst is the February birthstone and is the most commercially important purple quartz variety; heating can turn it yellow-orange, producing citrine.

Field identification & locations

Identify by its purple quartz appearance, glassy luster, hardness, and lack of cleavage; common sources include Brazil, Uruguay, Zambia, and Bolivia. This specimen may also be dyed or coated if color is unusually uniform or concentrated in surface fractures.