sedimentary

Rounded quartz-rich pebble

Chert or quartzite pebble (tentative; mostly microcrystalline quartz, SiO₂)

AI-generated identification · may be incorrect

Cream to tan, mottled reddish-brown surface with a dull to slightly waxy luster and no visible crystals; likely hardness about 6.5–7, with indistinct cleavage and specific gravity near 2.6. Its smooth shape indicates water abrasion.

Identified August 11, 2026More sedimentary →

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Physical properties

Formation & geological history

Probably weathered from a quartz-rich siliceous rock and rounded in a stream, beach, or glacial deposit; the original rock may be Precambrian to younger, but age cannot be determined from the photograph.

Uses & applications

Common pebbles have little commercial value, though attractive pieces may be used in crafts, landscaping, tumbling, or informal collections.

Geological facts

A steel knife or glass-scratch test can help distinguish quartz-rich material: quartzite or chert should resist scratching by a knife and may scratch glass. Exact identification requires examining fracture, translucency, and texture.

Field identification & locations

Common in river gravels, beaches, and glacial tills worldwide. The irregular cream-and-rust pattern could also indicate weathered jasper or iron-stained quartzite; a fresh broken surface would be diagnostic.