mineral
Iron-rich brown rock, possibly limonite/goethite
Limonite (hydrated iron oxides; commonly goethite, FeO(OH), with hematite)
AI-generated identification · may be incorrectBrown to reddish-brown, earthy to dull/submetallic luster, irregular massive texture, and no visible crystal faces or cleavage. Estimated Mohs hardness 4–5.5; typically dense and may leave a yellow-brown streak.
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Physical properties
Brown to reddish-brown, earthy to dull/submetallic luster, irregular massive texture, and no visible crystal faces or cleavage. Estimated Mohs hardness 4–5.5; typically dense and may leave a yellow-brown streak.
Formation & geological history
Forms by weathering and oxidation of iron-bearing minerals, often as a residual soil or cavity coating; its exact geological age cannot be determined from the image. The specimen may also be iron-stained quartz or another iron-rich rock.
Uses & applications
Used historically as an iron ore and natural ochre pigment; attractive pieces are collected, but it is generally not used for jewelry or construction.
Geological facts
“Limonite” is a field and commercial name rather than one pure mineral, because it is a mixture of hydrated iron oxides. Goethite-rich specimens commonly form botryoidal or earthy masses.
Field identification & locations
Look for a yellow-to-brown streak, high density, rusty coloration, and attraction only if magnetite is present. Common in weathered iron deposits worldwide; testing streak, hardness, and magnetism would improve identification.
