Rock Identifier
Limonite (FeO(OH)·nH2O) — mineral
mineral

Limonite

FeO(OH)·nH2O

AI-generated identification · may be incorrect

Hardness of 4-5.5 on the Mohs scale, yellowish-brown to dark brown color, earthy luster, amorphous or microcrystalline structure, specific gravity of 2.7-4.3.

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Physical properties

Hardness of 4-5.5 on the Mohs scale, yellowish-brown to dark brown color, earthy luster, amorphous or microcrystalline structure, specific gravity of 2.7-4.3.

Formation & geological history

Forms as a secondary mineral from the oxidation of iron-bearing minerals in weathered environments and sedimentary rock formations.

Uses & applications

Historically used as a low-grade iron ore and as a natural earth pigment for yellow and brown ochre paints.

Geological facts

Limonite is not a distinct mineral species, but rather a mixture of related hydrated iron oxides and hydroxides.

Field identification & locations

Identified easily by its characteristic yellowish-brown streak; commonly found in oxidized iron deposits worldwide.