gemstone

Amethyst cabochon jewelry

Amethyst, purple variety of quartz (SiO₂)

AI-generated identification · may be incorrect

Mohs hardness 7; vitreous luster; purple coloration from iron and irradiation; trigonal crystal structure, with no cleavage and conchoidal fracture. The pictured stone is polished/cut and mounted in jewelry, so natural crystal faces are absent.

Identified August 16, 2026More gemstone →

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Physical properties

Formation & geological history

Forms mainly in volcanic cavities as quartz-lined geodes, commonly during hydrothermal activity in basalt; deposits range from Paleozoic to Cenozoic in age. Major sources include Brazil, Uruguay, Zambia, and Bolivia.

Uses & applications

Used extensively in rings, pendants, beads, and ornamental objects; durable enough for everyday jewelry but can scratch or fade with prolonged strong sunlight.

Geological facts

Amethyst’s purple color varies from lilac to deep violet, and heating can turn it yellow-orange, producing citrine-like material. It is the traditional February birthstone.

Field identification & locations

Identify it by its transparent-to-translucent purple color, glassy luster, hardness, and lack of cleavage; beware purple glass or dyed quartz. The surrounding gold-colored metal and other stones are jewelry components, not part of the mineral specimen.