Rock Identifier
Iron-rich laterite or weathered ironstone (Laterite/limonite-rich ferricrete, composed mainly of iron oxyhydroxides such as goethite and limonite with clay minerals and quartz) — sedimentary
sedimentary

Iron-rich laterite or weathered ironstone

Laterite/limonite-rich ferricrete, composed mainly of iron oxyhydroxides such as goethite and limonite with clay minerals and quartz

AI-generated identification · may be incorrect

Reddish-brown, earthy to dull luster, irregular porous texture, and scattered dark metallic-looking grains; typically Mohs hardness about 4–6, with no obvious cleavage. The pale gray metallic patches may be quartz, weathered sulfide, or reflective iron-rich surfaces.

Identified More sedimentary
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Physical properties

Reddish-brown, earthy to dull luster, irregular porous texture, and scattered dark metallic-looking grains; typically Mohs hardness about 4–6, with no obvious cleavage. The pale gray metallic patches may be quartz, weathered sulfide, or reflective iron-rich surfaces.

Formation & geological history

Forms by intense tropical/subtropical chemical weathering, which removes soluble elements and concentrates iron and aluminum; commonly Quaternary to much older depending on the surface. The exact age and identification cannot be confirmed from an image alone.

Uses & applications

Used locally as iron ore, pigment, aggregate, and sometimes building stone; generally little jewelry value unless it contains attractive metallic mineralization.

Geological facts

Its red color primarily reflects hematite and hydrated iron oxides. A red-brown streak, earthy smell when wet, and attraction to a strong magnet would help assess iron content.

Field identification & locations

Common in tropical soils and weathering profiles, including parts of Africa, India, Brazil, Australia, and Southeast Asia. Test streak, magnetism, hardness, density, and acid reaction; avoid assuming the gray spots are precious metal.