gemstone

Tumbled amethyst

Amethyst, purple quartz (SiO₂), colored mainly by iron-related defects

AI-generated identification · may be incorrect

Hardness 7 Mohs; purple to violet with white/gray quartz bands, vitreous luster, transparent to translucent, trigonal crystal structure, and no cleavage. The rounded, glossy surface indicates tumbling/polishing; visible pale bands may be quartz or matrix.

Identified September 15, 2026More gemstone →

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Physical properties

Formation & geological history

Forms when silica-rich hydrothermal fluids fill cavities in volcanic rocks, commonly growing over millions of years. The specimen is processed rather than naturally rounded; age cannot be determined from the photograph.

Uses & applications

Used for inexpensive jewelry, carvings, ornaments, and mineral collections. This appears to be a common polished palm stone rather than gem-grade material.

Geological facts

Amethyst is the purple variety of quartz and is February’s birthstone. Color can fade with prolonged strong sunlight or heating.

Field identification & locations

Identify by its purple quartz appearance, glassy luster, hardness, and lack of cleavage; it should scratch glass but not be scratched by a steel knife. Amethyst is uncommon in ordinary surface deposits around Brittany/Normandy near 48.4°N, 1.6°W, so the regional location likely reflects a purchased or transported specimen.