sedimentary

Iron-rich concretion or weathered ironstone

Limonite/goethite-rich ironstone; commonly hydrated iron oxides, chiefly FeO(OH)·nH₂O

AI-generated identification · may be incorrect

Hardness about 4–5.5 Mohs; rusty brown, earthy to dull/submetallic luster, opaque, irregular massive texture, and high density (roughly 3–4 g/cm³). Often leaves a yellow-brown streak and may attract a magnet if magnetite is present.

Identified September 9, 2026More sedimentary →

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Physical properties

Formation & geological history

Forms when iron-bearing minerals oxidize and precipitate during weathering, groundwater alteration, or sedimentary cementation; typically geologically young relative to its host sediments, with age dependent on locality.

Uses & applications

Used historically as iron ore and natural ochre pigment; attractive pieces are collected, but ordinary specimens have little commercial value.

Geological facts

Its porous, irregular shape and rusty coating can resemble a meteorite, but terrestrial ironstone commonly has an earthy texture and yellow-brown streak rather than a dark fusion crust.

Field identification & locations

Common in weathered soils, stream gravels, limestone terrains, and sedimentary formations worldwide. Test streak on unglazed ceramic, density, magnetism, and inspect for vesicles or a fusion crust before considering meteorite identification.