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

Limonite

FeO(OH)•nH2O

AI-generated identification · may be incorrect

Hardness of 4 to 5.5 on the Mohs scale, yellowish-brown to dark brown color, earthy to submetallic luster, amorphous crystal structure.

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Physical properties

Hardness of 4 to 5.5 on the Mohs scale, yellowish-brown to dark brown color, earthy to submetallic luster, amorphous crystal structure.

Formation & geological history

Formed through the secondary alteration and weathering of iron-bearing minerals in oxidizing environments.

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 primarily by its characteristic yellowish-brown streak; found globally in gossans and weathered iron deposits.