sedimentary
Limonite Concretion
Hydrated iron oxide-hydroxide, FeO(OH)·nH2O
AI-generated identification · may be incorrectHardness of 4 to 5.5 on the Mohs scale, yellowish-brown to dark brown color, submetallic to earthy luster, amorphous crystal structure with no true cleavage.
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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, amorphous crystal structure with no true cleavage.
Formation & geological history
Formed through the oxidation and weathering of iron-bearing minerals in sedimentary environments or hydrothermal veins.
Uses & applications
Historically used as a pigment (ochre) and a minor ore of iron, but primarily collected as a geological curiosity.
Geological facts
Limonite is not a true distinct mineral, but rather a mixture of related hydrated iron oxides like goethite and lepidocrocite.
Field identification & locations
Easily identified by its characteristic yellowish-brown streak and concentric weathering rings; commonly found worldwide in oxidized iron deposits.
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