mineral

Yellow Ochre / Limonite

Hydrated ferric oxide (FeO(OH)·nH2O)

AI-generated identification · may be incorrect

Hardness: 4-5.5 (Mohs scale); Color: Yellow-brown to earthy gold; Luster: Dull, earthy; Crystal structure: Amorphous or cryptocrystalline; Cleavage: None; Specific gravity: 2.7-4.3

Hardness: 4-5
Color: Yellow-brown to earthy gold
Luster: Dull, earthy

Identified June 19, 2026More mineral →

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Physical properties

Hardness: 4-5.5 (Mohs scale); Color: Yellow-brown to earthy gold; Luster: Dull, earthy; Crystal structure: Amorphous or cryptocrystalline; Cleavage: None; Specific gravity: 2.7-4.3

Formation & geological history

Formed as a secondary mineral through the oxidation of iron-bearing mineral deposits or as a chemical precipitate in bogs, lakes, and marine environments.

Uses & applications

Used historically and currently as a natural earth pigment in paints, dyes, and coatings. Also used as a low-grade iron ore.

Geological facts

Ochre is one of the oldest pigments used by humans, found in cave paintings dating back over 75,000 years. Limonite is not a true mineral but a mixture of hydrated iron oxide minerals.

Field identification & locations

Identify in the field by its characteristic yellowish-brown 'rust' color and earthy, crumbly texture. It frequently leaves a yellowish streak on a ceramic plate. Found globally in iron-rich sedimentary environments.