gemstone

Tumbled amethyst (tentative)

Quartz, SiO₂; purple variety colored mainly by iron-related defects and irradiation

AI-generated identification · may be incorrect

Small polished translucent purple fragment with vitreous luster and likely conchoidal fracture; quartz hardness is Mohs 7, with no cleavage and specific gravity about 2.65. The image is insufficient to confirm exact identity or distinguish it from purple glass or another violet mineral.

Identified August 15, 2026More gemstone →

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Physical properties

Formation & geological history

Amethyst forms when iron-bearing quartz develops in volcanic cavities, commonly in basaltic geodes, through silica-rich groundwater; deposits range from Paleozoic to Cenozoic in age. Common sources include Brazil, Uruguay, Zambia, and Namibia.

Uses & applications

Used for cabochons, beads, carvings, crystal specimens, and ornamental objects; fine, strongly colored material has modest jewelry value.

Geological facts

Amethyst’s purple color can fade with prolonged heating or intense sunlight. Color zoning, natural crystal faces, and inclusions help separate it from glass.

Field identification & locations

Check for quartz-like hardness, natural zoning, inclusions, and lack of bubbles; a gemological refractometer or scratch testing is more reliable than the photo. Common localities include Brazil, Uruguay, Mexico, and the United States.