mineral

Limonite (with Goethite/Hematite glaze)

Hydrated Iron(III) Oxide-Hydroxide (FeO(OH)·nH2O)

Hardness: 4-5.5 (variable), Color: Yellow-brown to dark chocolate brown, Luster: Dull to sub-metallic or resinous, Structure: Amorphous or microcrystalline, Cleavage: None

Hardness: 4-5

Identified June 21, 2026More mineral →

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Physical properties

Hardness: 4-5.5 (variable), Color: Yellow-brown to dark chocolate brown, Luster: Dull to sub-metallic or resinous, Structure: Amorphous or microcrystalline, Cleavage: None

Formation & geological history

Formed as secondary mineral via oxidation/weathering of iron-rich minerals in sedimentary or hydrothermal environments. Often develops a hardened desert varnish or iron-rich glaze.

Uses & applications

Historically used as an iron ore; currently used as a natural earth pigment (yellow ochre) and occasionally in mineral collections.

Geological facts

Limonite is not a true mineral but a mixture of various hydrated iron oxides. It has been used as a pigment for cave paintings since prehistoric times.

Field identification & locations

Identify by its yellow-brown streak, earthy smell when moist, and lack of magnetism compared to magnetite. Found globally in bog iron deposits and weathered rock outcrops.

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Mineral/Rock

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Metamorphic Rock

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mineral