sedimentary

Rounded iron-rich river pebble

Likely ferruginous sandstone or iron-stained chert; exact identification requires testing

AI-generated identification · may be incorrect

Hardness likely 5.5–7 Mohs; brown to gray-brown, dull to weakly waxy luster, very fine-grained and dense, with no visible cleavage. Rounded, smooth surfaces indicate water abrasion; rusty speckling suggests iron oxides.

Identified September 11, 2026More sedimentary →

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Physical properties

Formation & geological history

Probably a weathered sedimentary cobble cemented or stained by hematite/goethite, later transported by a stream or shoreline. Its precise age and source cannot be determined visually.

Uses & applications

Mostly a geological or decorative specimen; if sufficiently hard and attractive, it may be used as a polished pebble or lapidary rough. It has little industrial value as an individual stone.

Geological facts

The reddish-brown coloration commonly comes from hematite and limonite coatings or cement. The subtle granular texture favors ferruginous sandstone over a massive metallic ore.

Field identification & locations

Look for a streak test, acid reaction, and hardness: quartz-rich material scratches glass and leaves a pale streak, while iron oxides often leave yellow-brown to reddish streaks. Common in river gravels, beaches, and glacial deposits.