Mineral

Yellow Ochre / Limonite

Limonite (FeO(OH)·nH2O)

Hardness: 4.0 - 5.5 Mohs scale; Color: Yellowish-brown to brownish-orange; Luster: Dull or earthy; Crystal structure: Amorphous; Cleavage: None; Specific gravity: 2.7 - 4.3.

Hardness: 4
Color: Yellowish-brown to brownish-orange
Luster: Dull or earthy

Identified February 13, 2026More mineral →

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Physical properties

Hardness: 4.0 - 5.5 Mohs scale; Color: Yellowish-brown to brownish-orange; Luster: Dull or earthy; Crystal structure: Amorphous; Cleavage: None; Specific gravity: 2.7 - 4.3.

Formation & geological history

Formed through the oxidation and hydration of iron-rich mineral ores (like pyrite or magnetite) in weathering zones or as a chemical precipitate in shallow marine or bog environments.

Uses & applications

Historically used as a natural pigment (yellow ochre) in paints and dyes. Historically mined as an iron ore in some regions; now primarily used in soil conditioners and for antique-style pigments.

Geological facts

Limonite is not technically a single mineral but a mixture of hydrated iron oxide minerals, mostly goethite. It was used by early humans for cave paintings and is also common in the 'gossan' or iron hat of metal deposits.

Field identification & locations

Identify in the field by its characteristic yellowish-brown streak (when rubbed on unglazed porcelain) and earthy appearance. Commonly found in oxidized zones of ore deposits or as sediment in wetlands. Collectors should look for stable, non-crumbling pieces.