sedimentary

Weathered iron-rich rock (probable laterite or limonite-bearing stone)

Goethite–limonite mixture, commonly written FeO(OH)·nH₂O, with possible quartz and clay minerals

AI-generated identification · may be incorrect

Brown, tan, and gray mottling; dull to earthy luster; rough, granular surface and rounded weathering. Likely Mohs hardness about 4–6, with no obvious cleavage; specific gravity commonly 2.7–4.3 depending on iron content.

Identified August 9, 2026More sedimentary →

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At a glance

Common name: Weathered iron-rich rock (probable laterite or limonite-bearing stone)
Scientific name: Goethite–limonite mixture, commonly written FeO(OH)·nH₂O, with possible quartz and clay minerals
Category: sedimentary
Identified: August 9, 2026
Method: Standard

AI Estimated Value

Typically $1–$10 as an ordinary hand specimen; perhaps $10–$30 if unusually colorful, locality-labeled, or scientifically documented.

Not an official valuation

AI estimate for general interest only — not an appraisal. Actual value depends on condition, provenance, and market demand. Verify with a professional before buying, selling, or insuring.

This identification was generated by AI and may contain errors. Verify important details before relying on them — and never use an AI result to judge whether a specimen is safe to handle. Read the full disclaimer

Physical properties

Formation & geological history

Likely formed by intense chemical weathering and iron-oxide/hydroxide concentration in soil or shallow bedrock, often producing laterite or ironstone. The exact age cannot be determined from the photograph and may range from recent weathering to ancient deposits.

Uses & applications

Usually a low-value geological curiosity; iron-rich laterite and limonite can be mined as iron ore, pigment, or aggregate, but this small specimen is not likely economically useful.

Geological facts

The rusty coloration comes from hydrated iron oxides, especially goethite and limonite. A yellow-brown streak and reddish-brown powder would support this identification.

Field identification & locations

Common in tropical and subtropical soils, weathered volcanic terrains, and ironstone deposits worldwide. Test streak on unglazed ceramic, inspect for magnetic response, and use acid only cautiously; a definitive identification requires hardness, streak, density, and mineralogical testing.