mineral

Iron-rich goethite/limonite specimen

Goethite, α-FeO(OH), commonly mixed with limonite and other iron oxides

AI-generated identification · may be incorrect

Rusty orange-brown surface with dark brown, earthy interior and a glossy, possibly wet or coated top. Goethite has Mohs hardness 5–5.5, a submetallic to earthy luster, and orthorhombic crystals; the pictured material appears massive rather than crystalline. Exact identification is uncertain from the image alone.

Identified September 23, 2026More mineral →

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Physical properties

Formation & geological history

Forms through oxidation and weathering of iron-bearing minerals, often in soils, bogs, and iron-ore deposits. These processes occur across geologic time; the specimen’s age cannot be determined visually.

Uses & applications

Iron oxides are important iron ores and pigments; attractive goethite specimens are collected, but this piece does not show obvious gem or industrial grade.

Geological facts

Goethite and related hydrated iron oxides are often collectively called limonite, though limonite is not a single mineral species.

Field identification & locations

Look for rusty brown to ochre color, earthy-to-submetallic surfaces, and a brownish-yellow streak. Common worldwide in weathered iron-rich rocks and soils; confirm with a streak and hardness test.