sedimentary

Rounded river or beach pebble

Likely quartz-rich sandstone or quartzite; exact identification requires a close-grained view and hardness test

AI-generated identification · may be incorrect

Pale gray, fine-grained, matte to weakly silky luster, smooth water-worn surface, and no visible crystals or cleavage. Likely hardness about 6–7 Mohs if quartz-rich; specific gravity roughly 2.6–2.7.

Identified August 12, 2026More sedimentary →

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Physical properties

Formation & geological history

The pebble was rounded by prolonged abrasion in a stream, river, or coastal environment. Its original rock may be sedimentary sandstone later compacted/cemented, or metamorphosed quartzite; age cannot be determined visually.

Uses & applications

Mostly a landscaping, decorative, or craft stone; it has little industrial or jewelry value unless confirmed as attractive quartzite or another distinctive material.

Geological facts

Its near-elliptical shape and smooth surface indicate transport and repeated impacts. The faint rusty patches likely reflect iron-oxide staining.

Field identification & locations

Common in river gravels, beaches, glacial deposits, and landscaping beds. Test an inconspicuous area: scratching glass suggests quartz-rich composition; a streak, acid reaction, and magnification can distinguish sandstone, quartzite, limestone, or concrete.