sedimentary

Polished brown river pebble

Likely iron-stained chert or fine-grained sandstone; exact identification is uncertain from the photograph

AI-generated identification · may be incorrect

Dark brown, rounded, wet-looking surface with subdued vitreous to earthy luster; likely hardness about 5–7 Mohs if chert, or 3–6 if sandstone. No visible crystals or cleavage; compact and fine-grained.

Identified August 28, 2026More sedimentary →

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At a glance

Common name: Polished brown river pebble
Scientific name: Likely iron-stained chert or fine-grained sandstone; exact identification is uncertain from the photograph
Category: sedimentary
Identified: August 28, 2026
Method: Standard

AI Estimated Value

Typically $1–$10 as a common polished or collected pebble; unusual color, pattern, or confirmed provenance could raise value to roughly $20–$50.

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

Rounded by abrasion in a stream or beach, with brown coloration probably from iron-oxide staining. The original rock may be Paleozoic or younger, but its geological age cannot be determined visually.

Uses & applications

Primarily a decorative or collector pebble; suitable for tumbling and crafts if sufficiently hard, but no significant industrial or jewelry value is evident.

Geological facts

The smooth shape reflects prolonged transport and abrasion rather than crystal growth. A wet surface can make an opaque stone appear darker and glossier than it is when dry.

Field identification & locations

Commonly found in river gravels, beaches, and glacial deposits. Test an inconspicuous area for streak, hardness, and acid reaction: chert resists scratching by steel, while sandstone is usually more granular and softer.