sedimentary

Ironstone (limonite/goethite-rich rock)

Limonite, a mixture of hydrated iron oxides, commonly including goethite (α-FeO(OH))

AI-generated identification · may be incorrect

Ochre-brown to yellow, earthy to subtly shiny surface; hardness and density vary with composition. The image lacks enough detail to establish crystal structure or cleavage.

Identified October 14, 2026More sedimentary →

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Physical properties

Ochre-brown to yellow, earthy to subtly shiny surface; hardness and density vary with composition. The image lacks enough detail to establish crystal structure or cleavage.

Formation & geological history

Typically forms through weathering and oxidation of iron-bearing minerals, or precipitation of iron oxides in sediments; age depends on the deposit.

Uses & applications

Iron-rich material may be used as low-grade iron ore or pigment; ordinary specimens are mainly collected for display.

Geological facts

“Limonite” is a field term for mixtures of hydrated iron oxides rather than a single mineral species.

Field identification & locations

The rusty brown color and irregular, earthy appearance suggest ironstone, but identification is uncertain from the photo alone; check for a yellow-brown streak and relatively high heft.