sedimentary

Iron-rich concretion or weathered ironstone pebble

Goethite–hematite-bearing limonite concretion (tentative)

AI-generated identification · may be incorrect

Small, rounded, dark reddish-brown specimen with dull to earthy luster and possible rusty iron-oxide patches. Likely hardness about 4–6 Mohs, no obvious cleavage, and moderate to high specific gravity; the image is insufficient for definitive identification.

Identified September 2, 2026More sedimentary →

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Physical properties

Formation & geological history

Probably formed when iron minerals precipitated and cemented sand or clay during weathering or groundwater movement; such concretions range from recent to geologically ancient. Common in soils, stream gravels, and sedimentary formations.

Uses & applications

Primarily a teaching or collecting specimen; ironstone and hematite ores can be mined for iron, while attractive pieces may be used decoratively. This small pebble has negligible commercial value.

Geological facts

Iron oxides commonly produce red, brown, orange, and black colors through hematite, goethite, and limonite. A reddish streak on unglazed porcelain and attraction to a strong magnet can help distinguish iron-rich material.

Field identification & locations

Common in sedimentary terrains and weathered gravel deposits worldwide, including Australia, India, North America, and Europe. Confirm with streak, magnetism, density, and a fresh surface; it could also be slag or another iron-rich rock if strongly vesicular or glassy.