mineral

Amethyst-bearing quartz with feldspar/mica matrix

Quartz, SiO₂, variety amethyst; likely pegmatitic matrix

AI-generated identification · may be incorrect

Purple vitreous quartz crystals occur with white-gray feldspar and dark mica or amphibole. Quartz hardness is 7, nonmetallic luster, hexagonal crystal structure, and no cleavage; specific gravity is about 2.65.

Identified September 21, 2026More mineral →

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Physical properties

Formation & geological history

Amethyst forms when trace iron in quartz is irradiated, commonly in cavities of volcanic rocks or hydrothermal veins; the coarse matrix suggests a pegmatite or metamorphic host. The specimen’s exact geological age and locality cannot be determined from the image.

Uses & applications

Used as a decorative and collecting specimen, and occasionally in jewelry when transparent enough for cutting; the attached matrix mainly adds display value.

Geological facts

The purple color is produced by iron-related defects in quartz, not by a separate purple mineral. Color intensity commonly varies within a single crystal or specimen.

Field identification & locations

Identify by purple quartz, glassy luster, and hardness sufficient to scratch ordinary glass, unlike softer purple fluorite. Common sources include Brazil, Uruguay, Zambia, and the United States.