mineral

Amethyst-bearing quartz geode or crystal cluster

Quartz, SiO₂; purple coloration from trace iron and irradiation

AI-generated identification · may be incorrect

Violet-to-gray quartz with a vitreous luster and numerous intergrown crystal faces; quartz hardness is Mohs 7, has no cleavage, conchoidal fracture, and specific gravity about 2.65. The dark appearance may reflect inclusions, coating, or shadow, so the exact specimen type is uncertain from one image.

Identified September 22, 2026More mineral →

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Physical properties

Formation & geological history

Likely formed in silica-rich cavities of volcanic rock, where quartz crystallized from hydrothermal fluids; amethyst commonly formed during the Cenozoic but can occur at many ages. It may be a natural cluster or a polished/partly shaped specimen.

Uses & applications

Used as a decorative and lapidary material, in jewelry, carvings, crystal collections, and ornamental displays; ordinary pieces have modest commercial value.

Geological facts

Amethyst is quartz colored primarily by iron-related defects; heating can convert its color toward yellow citrine. Crystal tips and drusy coatings are typical cavity-growth features.

Field identification & locations

Check for glassy luster, crystal faces, hardness greater than steel, and lack of cleavage; streak is white. Major sources include Brazil, Uruguay, Zambia, and Mexico. A clearer, strongly purple, naturally terminated cluster would be more diagnostic.