sedimentary

Rounded river gravel (mixed alluvial pebbles)

Polymictic alluvial gravel; commonly composed of quartzite, granite, basalt, sandstone, and quartz

AI-generated identification · may be incorrect

Mostly pebble-sized, rounded clasts with gray, tan, brown, and reddish colors; generally dull to slightly glassy. Hardness varies about Mohs 5–7, with no single crystal structure or cleavage because this is a mixed aggregate.

Identified August 19, 2026More sedimentary →

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At a glance

Common name: Rounded river gravel (mixed alluvial pebbles)
Scientific name: Polymictic alluvial gravel; commonly composed of quartzite, granite, basalt, sandstone, and quartz
Category: sedimentary
Identified: August 19, 2026
Method: Standard

AI Estimated Value

About $5–$30 per small bag; bulk landscaping gravel commonly costs $30–$150 per cubic yard, with ordinary individual pieces worth little.

Not an official valuation

AI estimate for general interest only — not an appraisal. Actual value depends on condition, provenance, and market demand. Verify with a professional before buying, selling, or insuring.

This identification was generated by AI and may contain errors. Verify important details before relying on them — and never use an AI result to judge whether a specimen is safe to handle. Read the full disclaimer

Physical properties

Formation & geological history

Formed when river or beach transport abrades and rounds fragments from older rocks; individual clasts may range from Precambrian to recent, while the gravel deposit is Quaternary or younger. The image shows naturally rounded material, possibly sold as landscaping gravel.

Uses & applications

Used for landscaping, drainage, paths, concrete aggregate, erosion control, and decorative ground cover; individual attractive pebbles may be collected but have little gemstone value.

Geological facts

The mixed composition reflects the upstream bedrock and transport history. Smoothness and size sorting indicate prolonged movement by flowing water or waves.

Field identification & locations

Identify it by rounded, water-worn shapes and varied lithologies; inspect broken surfaces or use hardness, streak, and acid tests to identify individual clasts. Common worldwide in river channels, alluvial terraces, beaches, and gravel pits.