Rock Identifier
Weathered iron-rich sandstone or ironstone (Ferruginous sandstone, composed mainly of quartz (SiO₂) cemented by iron oxides such as hematite (Fe₂O₃) and goethite (FeO(OH))) — sedimentary
sedimentary

Weathered iron-rich sandstone or ironstone

Ferruginous sandstone, composed mainly of quartz (SiO₂) cemented by iron oxides such as hematite (Fe₂O₃) and goethite (FeO(OH))

AI-generated identification · may be incorrect

Typically reddish-brown to gray, earthy to dull luster, coarse granular texture, and irregular fracture; hardness about 6–7 for quartz grains, with variable density and weak or absent cleavage. The image shows heavy weathering and iron-oxide staining, but exact identification requires a fresh surface and tests.

Identified More sedimentary
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Physical properties

Typically reddish-brown to gray, earthy to dull luster, coarse granular texture, and irregular fracture; hardness about 6–7 for quartz grains, with variable density and weak or absent cleavage. The image shows heavy weathering and iron-oxide staining, but exact identification requires a fresh surface and tests.

Formation & geological history

Formed when sand accumulated, lithified, and later became cemented or replaced by iron oxides in an oxidizing environment; age cannot be determined visually. Weathering has produced the rough, rusty surface and cavernous fractures.

Uses & applications

Used locally as building or paving stone and as an iron-bearing raw material when sufficiently rich; attractive pieces may be collected as natural specimens, though it is not normally a gemstone.

Geological facts

A streak test may produce a reddish-brown streak if hematite is abundant; magnetism can indicate magnetite, which is not obvious here.

Field identification & locations

Common in arid and oxidizing sedimentary terrains worldwide. Check graininess, acid reaction, streak, hardness, and magnetism; a laboratory analysis is needed to distinguish ferruginous sandstone from weathered ironstone or altered volcanic rock.