sedimentary

Rounded river pebble, likely weathered limestone or sandstone

Indeterminate carbonate or siliciclastic sedimentary rock; likely limestone (calcite-rich, CaCO₃) or lithic sandstone

AI-generated identification · may be incorrect

Brown-gray, dull to earthy luster, fine-grained and strongly rounded by abrasion; hardness approximately 3 if limestone or 6–7 if sandstone, with no visible crystals or cleavage. Exact identification requires a vinegar/HCl reaction and streak or hardness testing.

Identified August 25, 2026More sedimentary →

Explore Rounded river pebble, likely weathered limestone or sandstone in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

At a glance

Common name: Rounded river pebble, likely weathered limestone or sandstone
Scientific name: Indeterminate carbonate or siliciclastic sedimentary rock; likely limestone (calcite-rich, CaCO₃) or lithic sandstone
Category: sedimentary
Identified: August 25, 2026
Method: Standard

AI Estimated Value

Typically $1–$10 as an ordinary pebble; unusual color, fossil content, or 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

Formed from lithified sediment, then naturally smoothed during transport in a river, beach, or glacial environment; its depositional age cannot be determined from the photograph.

Uses & applications

Usually collected as a natural specimen, landscaping stone, or craft material; limestone may be used for aggregate and cement, while sandstone is used as building stone.

Geological facts

The smooth, flattened shape records prolonged mechanical abrasion and impacts during transport. Surface brown coloration commonly reflects iron-oxide staining or weathering.

Field identification & locations

Common worldwide in streambeds and gravel deposits; test an inconspicuous spot with dilute acid—vigorous fizz indicates calcite-rich limestone, while no reaction favors sandstone or another silicate rock.