sedimentary
Limonite Iron Concretion
Hydrated iron oxide-hydroxide, FeO(OH)·nH2O
AI-generated identification · may be incorrectHardness of 4-5.5 on the Mohs scale, earthy brown to yellowish-brown color, submetallic to dull luster, amorphous crystal structure with no true cleavage.
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Physical properties
Hardness of 4-5.5 on the Mohs scale, earthy brown to yellowish-brown color, submetallic to dull luster, amorphous crystal structure with no true cleavage.
Formation & geological history
Formed through the low-temperature oxidation and weathering of iron-bearing sulfide minerals and silicates in sedimentary environments.
Uses & applications
Historically used as a pigment (ochre) and minor iron ore; currently popular among mineral collectors as a curiosity.
Geological facts
Limonite is not a true distinct mineral species, but rather a natural mixture of related iron oxides like goethite and lepidocrocite.
Field identification & locations
Identified easily by its characteristic yellowish-brown streak and irregular concretionary shapes; found worldwide in weathered iron deposits.
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