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, submetallic to earthy luster, and 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, submetallic to earthy luster, and amorphous crystal structure.

Formation & geological history

Formed through the secondary oxidation and weathering of iron-bearing minerals in sedimentary, metamorphic, and igneous environments.

Uses & applications

Used historically as an iron ore and pigment ochre, and collected as a mineral specimen.

Geological facts

Limonite is not a true distinct mineral species, but rather a mixture of related hydrated iron oxide minerals like goethite and akaganeite.

Field identification & locations

Identified by its characteristic yellowish-brown streak and earthy appearance; commonly found in gossans above sulfide ore deposits.