gemstone

Tumbled amethyst quartz

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

AI-generated identification · may be incorrect

Mohs hardness 7; translucent violet to purple with white quartz zones, vitreous luster, and no visible cleavage. It appears polished/tumbled with a rounded shape; crystal structure is trigonal, though individual crystal faces are absent.

Identified September 21, 2026More gemstone →

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Physical properties

Formation & geological history

Forms in cavities of volcanic rocks, especially basalt, when silica-rich hydrothermal fluids deposit quartz and trace iron. Most amethyst formed during the late Paleozoic to Cenozoic in geodes and veins; exact age depends on locality.

Uses & applications

Used for inexpensive jewelry, ornaments, carvings, metaphysical objects, and mineral collections; high-quality deep-purple material is faceted or made into cabochons.

Geological facts

Amethyst is the birthstone for February and is the purple variety of quartz. Prolonged heating can turn it yellow-orange, producing citrine-like material.

Field identification & locations

Identify it by purple color, glassy luster, hardness sufficient to scratch glass, and quartz-like appearance; common sources include Brazil, Uruguay, Zambia, and Bolivia. This small polished piece is typically worth $3-$15 USD, more if unusually vivid and inclusion-rich.