sedimentary

Rounded quartz-rich pebble

Likely quartzite or quartz-rich sandstone; predominantly SiO₂

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs, gray-beige with brown iron-oxide staining, and a dull to slightly vitreous luster. Fine-grained and compact, with no obvious cleavage; its rounded shape reflects transport and abrasion.

Identified August 26, 2026More sedimentary →

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Physical properties

Formation & geological history

Probably derived from weathered quartz-rich sandstone or metamorphosed sandstone, then rounded in a stream, beach, or glacial environment. Its exact geological age and provenance cannot be determined from the photograph.

Uses & applications

Primarily a common decorative or teaching specimen; similar pebbles may be used in landscaping, aggregate, and occasionally lapidary work. This individual has little commercial value.

Geological facts

The pale body and rusty patches are consistent with quartz plus iron oxides, while the dark lines visible around it belong to the countertop rather than the specimen.

Field identification & locations

Test for quartzite with a steel knife or glass: it should resist scratching by a knife and may scratch glass; sandstone may be weaker or show granular grains. Common worldwide in river gravels, beaches, and glacial deposits.