mineral

Polished amethyst pyramid

Amethyst, purple quartz (SiO₂)

AI-generated identification · may be incorrect

Mohs hardness 7; purple to lavender coloration with white quartz zoning, vitreous luster, and trigonal crystal structure. The specimen is polished and shaped, so natural cleavage is not apparent; specific gravity is about 2.65.

Identified August 9, 2026More mineral →

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Physical properties

Formation & geological history

Amethyst forms when iron-bearing quartz is irradiated and develops purple color in cavities of volcanic rocks, especially basalt and rhyolite. Most commercial material formed in Mesozoic–Cenozoic volcanic settings, though the exact age cannot be determined from the image.

Uses & applications

Used as a gemstone, ornamental carving, meditation object, and collector specimen; quartz also has major industrial uses in glass, electronics, and abrasives.

Geological facts

The dark bands and cloudy areas likely represent alternating amethyst and milky quartz. Heat treatment can turn some amethyst yellow, producing citrine.

Field identification & locations

Identify by its purple color, glassy luster, hardness, and quartz-like appearance; common sources include Brazil, Uruguay, Zambia, and Bolivia. A definitive identification may require hardness or gemological testing.