sedimentary

Reddish-brown river pebble

Likely ferruginous sandstone or weathered reddish volcanic rock; exact identification requires a fresh surface and tests

AI-generated identification · may be incorrect

Fine-grained, matte, rounded and mildly flattened, with rusty brown coloration from iron oxides and sparse pale grains. Estimated hardness 5–7 Mohs; cleavage absent; specific gravity roughly 2.4–2.8.

Identified September 5, 2026More sedimentary →

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At a glance

Common name: Reddish-brown river pebble
Scientific name: Likely ferruginous sandstone or weathered reddish volcanic rock; exact identification requires a fresh surface and tests
Category: sedimentary
Identified: September 5, 2026
Method: Standard

AI Estimated Value

$1–$10 as an ordinary pebble; approximately $10–$30 if from a documented locality or sold as a polished/display specimen.

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

Natural abrasion rounded the specimen in a stream, beach, or glacial environment. Its precise geological age and parent formation cannot be determined from the photograph.

Uses & applications

Primarily a decorative or teaching specimen; comparable sandstone and volcanic pebbles are used as aggregate, paving material, and landscaping stone.

Geological facts

The red-brown color commonly indicates hematite or limonite coatings rather than a single red mineral. The smooth surface suggests prolonged transport or tumbling.

Field identification & locations

Check streak, acid reaction, grain texture, and hardness; sandstone feels granular and may scratch glass variably, while volcanic rock is commonly denser and more uniformly fine-grained. Common worldwide in river gravels, shorelines, and glacial deposits.