sedimentary

Mixed stream gravel and cobbles

Polylithic alluvial deposit; individual clasts are not identifiable at this resolution

AI-generated identification · may be incorrect

Rounded to subrounded gray, tan, and dark pebbles/cobbles, likely composed of quartzite, sandstone, slate, and volcanic or metamorphic rocks; hardness varies approximately 5–7 Mohs, with generally dull to earthy luster. Clast size and rounding indicate water transport rather than one solid rock specimen.

Identified August 18, 2026More sedimentary →

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At a glance

Common name: Mixed stream gravel and cobbles
Scientific name: Polylithic alluvial deposit; individual clasts are not identifiable at this resolution
Category: sedimentary
Identified: August 18, 2026
Method: Standard

AI Estimated Value

Generally $0–$5 per ordinary stone; selected unusual or attractive pieces may sell for $5–$25, but this mixed deposit has negligible collector value.

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

A modern Quaternary alluvial deposit formed as a stream eroded, transported, and sorted bedrock; individual stones may be much older than the deposit. The image shows a natural stream channel or gravel bar beneath woodland.

Uses & applications

Useful as natural drainage and landscaping gravel, aggregate, erosion control, and ornamental stone; attractive individual pieces may be collected, but no specific gemstone is evident.

Geological facts

The wide range of colors and lithologies reflects the upstream watershed. Smooth, rounded surfaces and concentration along the channel are strong evidence of fluvial action.

Field identification & locations

Identify it in the field by stream sorting, rounded edges, mixed rock types, and absence of cementation; exact identification requires close views, streak, hardness, acid, or locality information. Common worldwide in rivers and floodplains.