mineral

Iron-rich weathered stone, possibly limonite/goethite

Limonite (mixture of hydrated iron oxides), commonly goethite (α-FeO(OH))

AI-generated identification · may be incorrect

Orange-yellow to brown, earthy to dull luster, apparently massive and fine-grained; hardness roughly 4–5.5 Mohs, with no visible cleavage and relatively high density. The dark patches may be manganese oxides or host rock.

Identified August 13, 2026More mineral →

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Physical properties

Formation & geological history

Forms through intense oxidation and weathering of iron-bearing minerals, commonly as a soil concretion, laterite fragment, or ironstone; age depends on its parent material and may range from recent weathering to ancient deposits.

Uses & applications

Used historically as an iron ore and natural ochre pigment; attractive specimens are collected, but this small rough piece has little commercial value.

Geological facts

Limonite is not a single pure mineral but a field term for poorly crystalline hydrated iron oxides. Its vivid rust-orange color results from ferric iron.

Field identification & locations

Common in soils, iron-rich outcrops, mine dumps, and lateritic regions worldwide. A reddish-brown streak on unglazed porcelain, rusty coating, and attraction to a magnet if magnetite is present help distinguish it from ordinary sandstone.