sedimentary

Mixed tumbled river pebbles and beach stones

Polymictic alluvial gravel; components include quartz, chert, jasper, sandstone, and altered volcanic rocks

AI-generated identification · may be incorrect

Mostly rounded, water-worn specimens with brown, ochre, gray, cream, and reddish colors; surfaces are smooth to dull or slightly glossy. Hardness varies approximately Mohs 3–7, with quartz-rich pieces hardest; mineral composition, cleavage, and specific gravity vary by pebble.

Identified September 16, 2026More sedimentary →

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At a glance

Common name: Mixed tumbled river pebbles and beach stones
Scientific name: Polymictic alluvial gravel; components include quartz, chert, jasper, sandstone, and altered volcanic rocks
Category: sedimentary
Identified: September 16, 2026
Method: Standard

AI Estimated Value

About $5–$25 for the mixed group; selected attractive jasper, agate, or unusual specimens typically range from $2–$20 each.

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

These are likely natural river or beach gravels transported, abraded, and deposited by flowing water or waves; their ages range from ancient source-rock ages to recent Quaternary deposition. Several pieces appear polished or tumbled after collection.

Uses & applications

Used for lapidary work, crafts, landscaping, aquarium decoration, jewelry, and geological teaching collections; attractive jasper or agate pieces may be cabbed or polished.

Geological facts

The assortment is not one rock type: the reddish-orange pieces may be jasper or iron-rich sandstone, translucent pieces quartz or chalcedony, and dark patterned pieces volcanic or metamorphic rock.

Field identification & locations

Identify individual stones by hardness, translucency, grain, and acid reaction; quartz/chalcedony scratch glass, while sandstone and calcite-rich stones generally do not. Common sources include riverbeds, beaches, and commercial landscaping or craft suppliers.