mineral

Amethyst (tumbled quartz)

Quartz, SiO₂; purple variety known as amethyst

AI-generated identification · may be incorrect

Translucent purple with a vitreous luster and irregular pale matrix; hardness 7 Mohs, trigonal crystal structure, no cleavage, and specific gravity about 2.65. The rounded shape indicates tumbling; the pale attached material may be host rock.

Identified September 25, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich fluids deposit quartz in cavities and veins, with trace iron and irradiation producing purple color. Amethyst deposits occur in rocks of many ages, commonly in volcanic geodes and hydrothermal veins.

Uses & applications

Used in jewelry, ornaments, and mineral collections; this small tumbled piece is primarily a decorative or educational specimen.

Geological facts

Amethyst is the traditional February birthstone. Its color can fade with prolonged strong sunlight or heat.

Field identification & locations

Identify by its purple color, glassy luster, hardness, and lack of cleavage; common sources include Brazil, Uruguay, Zambia, and parts of the United States. The attached cream-colored area may be matrix, but cannot be identified confidently from the image.