sedimentary

Rounded quartz-rich pebble

Likely quartzite or quartz-rich sandstone; predominantly SiO₂

AI-generated identification · may be incorrect

Pale tan, fine-grained, and weakly granular with a dull to slightly silky luster; apparent hardness about 6–7 Mohs, no visible cleavage, and moderate-to-high density. Its smooth, flattened shape reflects abrasion during transport.

Identified August 28, 2026More sedimentary →

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Physical properties

Formation & geological history

Probably formed from quartz-rich sediment later cemented or metamorphosed, then rounded by river, beach, or glacial action. The original rock may be Precambrian to younger, but age cannot be determined visually.

Uses & applications

Commonly used as landscaping stone, aggregate, decorative pebble, or a lapidary material; this specimen has little jewelry value unless it shows attractive patterns or can be polished.

Geological facts

Quartz-rich rocks resist weathering, allowing them to survive long transport and become rounded. The central rough patch may be a weathered inclusion, surface fracture, or adhering mineral coating.

Field identification & locations

Look for a glassy fracture, inability to scratch it with a steel knife, and possible glass-scratching ability; dilute acid should produce no fizz if quartz-rich. Common in streambeds, beaches, gravel deposits, and glacial tills.