sedimentary

Weathered brown iron-rich pebble

Likely ferruginous sandstone or ironstone; exact identification requires testing

AI-generated identification · may be incorrect

Hardness roughly 5–7 Mohs; brown to reddish-brown, earthy to dull luster, fine-grained and massive, with pale gray weathering or cement-filled areas. No visible crystal faces or cleavage; density likely moderate to high from iron minerals.

Identified September 10, 2026More sedimentary →

Explore Weathered brown iron-rich pebble in the encyclopedia →

Identify your own rocks.

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

App Store Google Play

Physical properties

Formation & geological history

Probably formed from sand or clay cemented by iron oxides, then rounded and sculpted by stream or beach transport and weathering. Its precise geological age cannot be determined from the photograph.

Uses & applications

Primarily a natural specimen or curiosity; ferruginous sandstone may be used locally as building stone or aggregate, but this small rounded piece has little industrial value.

Geological facts

The dark brown color commonly reflects hematite, goethite, or limonite coatings and cement. The irregular lobes may be natural erosion, concretionary growth, or a fragment of an iron-rich rock.

Field identification & locations

Look for a rusty streak, moderate heft, granular texture, and possible attraction to a strong magnet if magnetite is present; a steel file, streak plate, and acid test would help distinguish ironstone from basalt or slag. Common in weathered sedimentary terrains, river gravels, and beaches.