gemstone

Tumbled amethyst

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

AI-generated identification · may be incorrect

Mohs hardness 7; translucent purple body with vitreous luster, commonly showing subtle zoning and no visible cleavage. Quartz has a trigonal crystal structure and specific gravity near 2.65; this specimen is polished/tumbled.

Identified August 13, 2026More gemstone →

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Physical properties

Formation & geological history

Amethyst forms mainly in volcanic geodes when silica-rich fluids deposit quartz in cavities, with iron impurities later irradiated to produce purple color. Deposits range from ancient to relatively young, commonly associated with basaltic volcanic rocks.

Uses & applications

Used for inexpensive jewelry, carvings, décor, and mineral collecting. Tumbled pieces are generally valued for color, translucency, and polish rather than rarity.

Geological facts

Purple intensity can fade with prolonged heat or strong sunlight. The image shows a likely commercial tumbled amethyst, though dyed glass or other purple material cannot be ruled out without testing.

Field identification & locations

Common sources include Brazil, Uruguay, Zambia, and Bolivia. Identify by hardness, glassy luster, natural color zoning, and resistance to scratching by steel; definitive confirmation requires refractive-index or other gemological testing.