sedimentary

Iron-rich laterite or weathered ironstone

Ferricrete/limonite-rich ironstone; primarily goethite (FeO(OH)) and hematite (Fe₂O₃), with clay minerals

AI-generated identification · may be incorrect

Hardness about 4–6 Mohs; rusty orange-red, earthy to dull luster, porous and irregular, with no visible crystal faces or cleavage. The coloration comes from hydrated and oxidized iron minerals.

Identified August 7, 2026More sedimentary →

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Physical properties

Hardness about 4–6 Mohs; rusty orange-red, earthy to dull luster, porous and irregular, with no visible crystal faces or cleavage. The coloration comes from hydrated and oxidized iron minerals.

Formation & geological history

Forms when iron-bearing minerals intensely weather in warm, humid environments, concentrating iron oxides and hydroxides in residual soil or cementing sediment. Such surfaces may range from relatively young soil horizons to ancient lateritic profiles.

Uses & applications

Used locally as low-grade iron ore, road aggregate, and occasionally decorative stone; ordinary specimens have little jewelry value.

Geological facts

Limonite is a variable mixture rather than a single pure mineral, while goethite and hematite commonly produce the same rusty appearance. A reddish streak and possible attraction to a strong magnet support an ironstone identification.

Field identification & locations

Common in tropical and subtropical weathering zones, including Australia, Africa, India, Brazil, and the southeastern United States. A streak test on unglazed porcelain, density, and laboratory iron analysis are more reliable than appearance alone.