mineral

Amethyst (rough quartz fragment)

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

AI-generated identification · may be incorrect

Mohs hardness 7; pale purple to violet, translucent, with a vitreous luster and likely conchoidal fracture. Quartz is trigonal and lacks cleavage; specific gravity is about 2.65.

Identified August 17, 2026More mineral →

Explore Amethyst (rough quartz fragment) in the encyclopedia →

Identify your own rocks.

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

App Store Google Play

Physical properties

Mohs hardness 7; pale purple to violet, translucent, with a vitreous luster and likely conchoidal fracture. Quartz is trigonal and lacks cleavage; specific gravity is about 2.65.

Formation & geological history

Forms when silica-rich hydrothermal fluids fill cavities in volcanic rocks, especially basaltic geodes; much amethyst formed during the Mesozoic and younger periods. The image shows a small, likely naturally fractured or lightly shaped fragment.

Uses & applications

Used for jewelry, carvings, display specimens, and lapidary work; common pieces have modest commercial value.

Geological facts

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

Field identification & locations

Identify it by its purple color, glassy luster, hardness, and lack of cleavage; test cautiously because scratching can damage the specimen. Major sources include Brazil, Uruguay, Zambia, Bolivia, and Mexico.