sedimentary

Mixed rounded river gravel

Polymictic alluvial gravel; likely mixtures of quartzite, granite, basalt, sandstone, and other silicate rocks

AI-generated identification · may be incorrect

Pebbles are mostly rounded and water-worn, with gray, tan, pink, green, and bluish colors; textures range from granular to fine-grained, with generally dull to vitreous luster. Hardness varies approximately Mohs 3–7 depending on composition; no single crystal structure or cleavage applies.

Identified August 16, 2026More sedimentary →

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At a glance

Common name: Mixed rounded river gravel
Scientific name: Polymictic alluvial gravel; likely mixtures of quartzite, granite, basalt, sandstone, and other silicate rocks
Category: sedimentary
Identified: August 16, 2026
Method: Standard

AI Estimated Value

Typically $0.05–$2 per piece or $20–$100 per landscaping load; unusually colorful or collectible individual stones may sell for $5–$30.

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 by erosion, transport, and abrasion in a river or stream, then deposited as alluvium; the individual clasts may represent rocks of widely different ages and origins. This is a modern surface deposit rather than one unified rock specimen.

Uses & applications

Used for landscaping, drainage, pathways, garden borders, concrete aggregate, and erosion control; selected attractive pieces may be used in crafts or aquaria.

Geological facts

The image shows a collection rather than a single identifiable mineral. Rounded shapes indicate sustained transport by flowing water or wave action.

Field identification & locations

Identify individual stones by testing hardness, examining grain size, and checking for visible minerals: quartz-rich pieces resist scratching, dark fine-grained stones may be basalt, and pink speckled stones may be granite. Common in riverbeds, floodplains, and glacial outwash.