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, submetallic to earthy luster, amorphous or cryptocrystalline structure.
Identified More mineral →
Explore Limonite Concretion in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness of 4-5.5 on the Mohs scale, yellowish-brown to dark brown color, submetallic to earthy luster, amorphous or cryptocrystalline structure.
Formation & geological history
Formed through the oxidation and weathering of iron-bearing minerals and rocks in sedimentary environments and hydrothermal veins.
Uses & applications
Used historically as a pigment (ochre) and minor iron ore, as well as valued by collectors for unusual botryoidal shapes.
Geological facts
Often called 'bog iron' when formed in wetlands, limonite frequently pseudomorphs after other minerals like pyrite, retaining the original crystal shape while changing composition.
Field identification & locations
Identified by its distinctive yellowish-brown streak and irregular, mammillary, or stalactitic forms. Commonly found worldwide in oxidized iron deposits.
