mineral

Amethyst-bearing quartz cluster

Quartz, SiO₂; purple coloration from trace iron and irradiation

AI-generated identification · may be incorrect

Hardness 7 Mohs; translucent colorless to lilac-purple crystals with vitreous luster, conchoidal fracture, and hexagonal/trigonal crystal symmetry. The specimen appears partly coated or associated with milky quartz and possibly minor iron staining.

Identified September 6, 2026More mineral →

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Physical properties

Formation & geological history

Crystals formed when silica-rich hydrothermal fluids filled cavities in volcanic rocks, commonly basaltic vesicles; purple amethyst developed through iron impurities and natural radiation. Most examples formed during relatively young volcanic episodes, commonly Mesozoic to Cenozoic, depending on locality.

Uses & applications

Used for jewelry, carvings, polished specimens, and mineral collecting; quartz is also important industrially in glass, abrasives, electronics, and engineered stone.

Geological facts

Amethyst is the purple variety of quartz and is February’s birthstone. Heating can turn some amethyst yellow-orange, producing citrine-like material.

Field identification & locations

Identify by purple transparent quartz crystals, glassy luster, hardness sufficient to scratch ordinary glass, and lack of cleavage. Common sources include Brazil, Uruguay, Zambia, Namibia, Mexico, and the United States.