mineral

Amethyst quartz crystal

Quartz, silicon dioxide (SiO₂), purple variety amethyst

AI-generated identification · may be incorrect

Hardness 7 Mohs; purple to violet with translucent areas and a vitreous luster. It has a hexagonal crystal structure and indistinct cleavage, commonly breaking conchoidally; the pale tip may be quartz or weathered matrix.

Identified August 9, 2026More mineral →

Explore Amethyst quartz crystal in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Forms when iron-bearing quartz is irradiated within volcanic cavities, especially basaltic geodes and veins. Crystals range from ancient to relatively young, depending on the host rock and deposit.

Uses & applications

Used as a gemstone, ornamental specimen, and metaphysical collectible; also sold as crystal points and geode material. This rough, hand-sized specimen has modest commercial value.

Geological facts

Purple color results mainly from irradiation-related defects involving iron impurities. Heating can turn amethyst yellow-orange, producing citrine.

Field identification & locations

Identify it by purple quartz color, glassy luster, hardness, and lack of prominent cleavage; it should scratch glass but not be scratched by a steel knife. Common sources include Brazil, Uruguay, Zambia, and Mexico.