sedimentary

Alluvial stream gravel (mixed rock specimens)

Polymictic fluvial deposit; likely mixtures of quartzite, sandstone, shale, chert, basalt, and granite-derived minerals

AI-generated identification · may be incorrect

Rounded to subrounded pebbles and sand, mostly dark gray, brown, tan, and reddish; surfaces are wet and show variable dull to glassy luster. Individual hardness likely ranges about Mohs 3–7, with quartz-rich pieces near 7; no single crystal structure or cleavage applies to the mixed material.

Identified September 6, 2026More sedimentary →

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At a glance

Common name: Alluvial stream gravel (mixed rock specimens)
Scientific name: Polymictic fluvial deposit; likely mixtures of quartzite, sandstone, shale, chert, basalt, and granite-derived minerals
Category: sedimentary
Identified: September 6, 2026
Method: Standard

AI Estimated Value

$0–$10 for ordinary mixed gravel; approximately $10–$100+ only if gold, gemstones, or unusually attractive specimens are recovered.

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 weathering and river transport that abrated and sorted rock fragments; the deposit is modern to Holocene in age. The red pan contains sediment collected from the active stream bed, not one coherent rock.

Uses & applications

Used for panning and prospecting, aggregate, landscaping, drainage, and educational collections; valuable minerals cannot be confirmed from this photograph alone.

Geological facts

The rounded shape and mixed colors indicate fluvial transport, while angular grains and dark lithic fragments reflect nearby bedrock sources. A magnet, streak testing, hardness testing, and careful examination for visible gold or heavy minerals would aid identification.

Field identification & locations

Common in active rivers worldwide. Identify individual pieces separately: quartz/chert are hard and scratch glass, shale splits into layers, basalt is dark and fine-grained, and granite shows visible interlocking crystals.