mineral
Limonite Concretion
Hydrated Iron Oxide-Hydroxide, FeO(OH)·nH2O
AI-generated identification · may be incorrectHardness of 4-5.5 on the Mohs scale, yellowish-brown to dark brown color, earthy to submetallic luster, amorphous crystal structure, and a yellowish-brown streak.
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Physical properties
Hardness of 4-5.5 on the Mohs scale, yellowish-brown to dark brown color, earthy to submetallic luster, amorphous crystal structure, and a yellowish-brown streak.
Formation & geological history
Formed through the secondary oxidation and weathering of primary iron-bearing minerals in sedimentary, igneous, and metamorphic environments.
Uses & applications
Historically used as a yellow ochre pigment, an ore of iron, and commonly collected as a natural geological curiosity.
Geological facts
Limonite is not a distinct mineral species, but rather a catch-all term for natural mixtures of related iron oxide minerals 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.
