gemstone

Amethyst crystal fragment

Quartz, silicon dioxide (SiO₂), purple variety colored mainly by iron and irradiation

AI-generated identification · may be incorrect

Mohs hardness 7; translucent violet color, vitreous luster, hexagonal crystal structure, and indistinct cleavage with conchoidal fracture. The specimen appears to be a small rough or partly polished crystal fragment.

Identified August 18, 2026More gemstone →

Explore Amethyst crystal fragment 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

Amethyst forms in cavities of volcanic rocks, especially basalt, when silica-rich hydrothermal fluids deposit quartz; its purple color develops from iron impurities and natural radiation. Most commercial material comes from Brazil, Uruguay, Zambia, and Bolivia, generally formed in Mesozoic to younger volcanic settings.

Uses & applications

Used as a gemstone, ornamental mineral, and collector specimen; larger transparent pieces are faceted or made into cabochons and geodes. Small common fragments have modest value.

Geological facts

Amethyst is the purple variety of quartz and is the birthstone for February. Heating can turn it yellow-orange, producing citrine or ametrine-like material.

Field identification & locations

Identify it by purple quartz color, glassy luster, hardness sufficient to scratch ordinary glass, and lack of strong cleavage; beware purple glass or dyed quartz. Common localities include Brazil, Uruguay, Zambia, and Mexico.