mineral

Limonite

FeO(OH)·nH2O

Hardness: 4 to 5.5 on the Mohs scale. Color: Brown, yellowish-brown, or yellow-ochre. Luster: Earthy, submetallic, or silky. Crystal structure: Amorphous or microcrystalline, typically forming as botryoidal, mammillary, or stalactitic masses. Streak: Yellowish-brown. Specific gravity: 2.7 to 4.3.

Hardness: 4 to 5
Color: Brown, yellowish-brown, or yellow-ochre
Luster: Earthy, submetallic, or silky

Identified August 5, 2026More mineral →

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Physical properties

Formation & geological history

Formed as a secondary mineral resulting from the oxidation and weathering of various iron-bearing minerals, commonly found in gossans and iron-rich sedimentary deposits or bog environments.

Uses & applications

Historically used as a pigment (yellow ochre) and as a minor ore of iron. Highly prized by mineral collectors for unusual botryoidal or iridescent specimens.

Geological facts

Limonite is not a single distinct mineral, but rather a mixture of related hydrated iron oxides, most commonly goethite, lepidocrocite, and sometimes hematite.

Field identification & locations

Can be identified in the field by its characteristic yellowish-brown streak and earthy texture. Commonly found worldwide in oxidized zones of iron ore deposits.