gemstone

Polished purple amethyst cabochon

Amethyst, purple variety of quartz (SiO₂)

AI-generated identification · may be incorrect

Mohs hardness 7; transparent to translucent purple, with a vitreous luster and trigonal crystal structure. The image shows a polished, rounded cabochon, so natural crystal faces and cleavage are not visible.

Identified September 24, 2026More gemstone →

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Physical properties

Formation & geological history

Amethyst forms in silica-rich fluids, commonly lining cavities in volcanic rock; its purple color is linked to trace iron and natural irradiation. Deposits range from millions to hundreds of millions of years old; the specimen’s exact age and source cannot be determined from the image.

Uses & applications

Used in jewelry, carvings, and mineral collections; also sold as polished cabochons and decorative stones.

Geological facts

Amethyst is quartz colored by iron-related defects in its crystal lattice. It can fade with prolonged exposure to strong sunlight or heat.

Field identification & locations

Identify by its purple color, glassy luster, and hardness: quartz can scratch glass and is not easily scratched by a steel blade. Major sources include Brazil, Uruguay, Zambia, and South Korea.