gemstone

Amethyst cabochon ring

Amethyst, purple quartz (SiO₂), colored primarily by iron-related defects and irradiation

AI-generated identification · may be incorrect

Mohs hardness 7; purple, translucent to transparent, vitreous luster, trigonal crystal structure, and no true cleavage (conchoidal fracture). The stone is polished into an oval cabochon and set in metal, with visible internal veils/inclusions.

Identified August 16, 2026More gemstone →

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Physical properties

Formation & geological history

Forms mainly in silica-rich volcanic cavities when quartz-bearing fluids deposit crystals in basaltic geodes; major deposits are in Brazil, Uruguay, Zambia, and Bolivia. Most gem amethyst is geologically young relative to host volcanic rocks, commonly tens to hundreds of millions of years old.

Uses & applications

Used extensively in jewelry, carvings, and mineral collections; lower-grade material is used for decorative objects and polished slices. The pictured ring’s value depends strongly on metal, weight, color, clarity, and craftsmanship.

Geological facts

Deep, even “Siberian” purple with red flashes is traditionally most prized, while heat treatment can produce citrine or green quartz. Amethyst is February’s birthstone.

Field identification & locations

Identify by its purple color, glassy luster, hardness, and lack of cleavage; it should scratch glass but not be scratched by a steel knife. Estimated value: about $20–$150 for a typical silver fashion ring, or $150–$500+ for superior natural color and fine workmanship.