mineral

Likely ironstone concretion or weathered iron-rich rock

Goethite/hematite-bearing limonite (FeO(OH)·nH₂O / Fe₂O₃)

AI-generated identification · may be incorrect

Brown, earthy to submetallic, porous and strongly weathered; apparent hardness about 4–6 Mohs, with no visible crystal structure or cleavage. The central cavity and included rounded nodule suggest a natural concretion, though its unusually symmetrical shape may indicate human modification.

Identified September 7, 2026More mineral →

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Physical properties

Formation & geological history

Iron-rich groundwater can cement sediment into spherical concretions and produce limonite/goethite coatings through oxidation; exact age and locality cannot be determined from the image. It may also be a weathered, worked iron-bearing object rather than a purely natural specimen.

Uses & applications

Common ironstone has limited economic value but is used as iron ore, pigment, and a collector specimen; it is not typically used as a gemstone.

Geological facts

A magnet test, streak test, and close inspection of the hole can distinguish ironstone from slag or manufactured material. Black-brown streak, heft, and attraction to a magnet support iron-rich composition.

Field identification & locations

Look for a yellow-brown to reddish-brown streak, high density, and possible magnetism; natural concretions usually show irregular surfaces and internal concentric structure. Common in weathered soils and sedimentary ironstone deposits worldwide.