metamorphic

Tumbled quartz-rich stone, possibly quartzite

Quartzite (mostly SiO₂), visually similar to chert or weathered quartz sandstone

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; rounded and smoothed, gray-beige with faint reddish iron staining, dull to weakly vitreous luster, and no visible cleavage. Fine-grained massive texture; specific gravity typically 2.6–2.7.

Identified September 22, 2026More metamorphic →

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Physical properties

Formation & geological history

Likely a naturally quartz-rich sedimentary rock metamorphosed by heat and pressure, then rounded by abrasion or deliberate tumbling. Quartzite commonly forms during regional metamorphism, generally from Precambrian through younger geological ages.

Uses & applications

Suitable mainly as a decorative or educational specimen; quartzite is also used as crushed stone, aggregate, paving, and durable building stone. This ordinary tumbled piece has little jewelry value.

Geological facts

The apparent polish and uniformly rounded shape strongly suggest human tumbling rather than natural weathering. Iron-oxide staining accounts for the scattered reddish-brown patches.

Field identification & locations

Test with a steel file or glass: genuine quartzite should resist scratching glass and show a granular quartz texture; acid will not fizz. Common sources include metamorphic belts worldwide, especially Brazil, India, the United States, and Scandinavia.