Rock Identifier
Brown iron-rich rock, likely limonite/goethite-bearing stone (Limonite (hydrated iron oxides; commonly goethite, FeO(OH), with hematite)) — mineral
mineral

Brown iron-rich rock, likely limonite/goethite-bearing stone

Limonite (hydrated iron oxides; commonly goethite, FeO(OH), with hematite)

AI-generated identification · may be incorrect

Brown to golden-brown, earthy to submetallic luster, granular and irregular; typically Mohs hardness 4–5.5, no consistent crystal form or cleavage, and relatively high specific gravity around 3.3–4.3.

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Physical properties

Brown to golden-brown, earthy to submetallic luster, granular and irregular; typically Mohs hardness 4–5.5, no consistent crystal form or cleavage, and relatively high specific gravity around 3.3–4.3.

Formation & geological history

Forms through oxidation and weathering of iron-bearing minerals, commonly as soil concretions, gossan, or cavity coatings; generally a young surficial product, though it may overprint rocks of any geological age.

Uses & applications

Used historically as an iron ore and pigment (yellow ochre to brown umber); attractive specimens are collected, but this rough piece has little commercial value.

Geological facts

Limonite is a field and trade term rather than a single precisely defined mineral species; its color comes from hydrated iron oxides and it commonly leaves a yellow-brown streak.

Field identification & locations

Likely identification is supported by the rusty brown color, earthy texture, and heavy appearance; test its yellow-brown streak and compare density. Common in weathered iron deposits worldwide, including mining districts and lateritic soils.