mineral

Polished amethyst-bearing quartz

Quartz, SiO₂; purple coloration from irradiation and trace iron

AI-generated identification · may be incorrect

Mohs hardness 7; translucent pale greenish-gray and purple zones, vitreous luster, trigonal crystal structure, and no prominent cleavage. The rounded, polished surface obscures natural crystal form; green areas may represent included or altered quartz, but could also be fluorite or another mineral.

Identified August 15, 2026More mineral →

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Physical properties

Formation & geological history

Amethyst forms in gas cavities and fractures of volcanic rocks when silica-rich fluids deposit quartz, commonly during the Mesozoic to Cenozoic. The specimen appears human-polished and cannot be age-dated from the image.

Uses & applications

Used as a gemstone, ornamental stone, and collector specimen; polished pieces are commonly made into cabochons and carvings.

Geological facts

Purple color is caused primarily by iron-related defects in quartz. Strongly zoned purple-white-green material is sometimes sold as “amethyst,” “prasiolite,” or trade-name material, though visual identification alone is uncertain.

Field identification & locations

Likely quartz if it scratches glass and shows a white streak; quartz has no cleavage and a conchoidal fracture. Common sources include Brazil, Uruguay, Zambia, and Madagascar.