mineral

Amethyst (rough purple quartz)

Quartz, SiO₂; purple color from trace iron and natural irradiation

AI-generated identification · may be incorrect

Mohs hardness 7; translucent purple with a vitreous luster and trigonal crystal structure. Quartz has no cleavage and shows conchoidal fracture; this piece appears rough and fractured.

Identified September 26, 2026More mineral →

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Physical properties

Mohs hardness 7; translucent purple with a vitreous luster and trigonal crystal structure. Quartz has no cleavage and shows conchoidal fracture; this piece appears rough and fractured.

Formation & geological history

Forms as quartz crystals in silica-rich hydrothermal veins and volcanic geodes, commonly during late-stage cooling. Its exact age and locality cannot be determined from the image.

Uses & applications

Used in jewelry, carvings, and mineral collections; lower-grade material is also used decoratively.

Geological facts

Amethyst is the purple variety of quartz; heat treatment can turn some amethyst yellow or greenish and alter its color.

Field identification & locations

Identify by its purple color, glassy luster, hardness, and lack of cleavage; it occurs worldwide, notably in Brazil, Uruguay, and Zambia. The image shows a small, unpolished fragment, with no visible locality markers.