gemstone

Likely tumbled amethyst

Amethyst, purple quartz (SiO₂)

AI-generated identification · may be incorrect

Typically purple with vitreous luster, hardness 7 Mohs, no cleavage, hexagonal crystal structure, and specific gravity about 2.65. The small blurred object appears dark violet and translucent, though identification is limited by the image.

Identified September 7, 2026More gemstone →

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Physical properties

Formation & geological history

Forms when iron-bearing quartz is irradiated in volcanic cavities, especially basaltic geodes; most deposits are Cenozoic to Paleozoic in age. Common sources include Brazil, Uruguay, Zambia, and Bolivia.

Uses & applications

Used for cabochons, beads, carvings, tumbled stones, and collector specimens; high-quality crystals are used in jewelry. Common tumbled pieces have modest value.

Geological facts

Its purple color results mainly from irradiation-related color centers involving iron. Heating can turn some amethyst yellow or orange, producing citrine-like material.

Field identification & locations

Identify by purple color, glassy luster, quartz-like hardness, and lack of cleavage; it should scratch ordinary glass but not be scratched by a steel knife. Common locations include basalt geodes and hydrothermal veins.