sedimentary

Iron-rich weathered rock, likely limonite-bearing sandstone or ironstone

Limonite/goethite-bearing ferruginous sandstone or ironstone; limonite is an amorphous mixture dominated by hydrated iron oxides, commonly approximated as FeO(OH)·nH₂O

AI-generated identification · may be incorrect

Yellow-brown to reddish-brown earthy surface with dull to weakly silky luster and probable granular sandstone texture; hardness roughly 4–6, no obvious cleavage, and moderate-to-high specific gravity from iron oxides. The image alone cannot confirm the exact rock type or mineral proportions.

Identified August 29, 2026More sedimentary →

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At a glance

Common name: Iron-rich weathered rock, likely limonite-bearing sandstone or ironstone
Scientific name: Limonite/goethite-bearing ferruginous sandstone or ironstone; limonite is an amorphous mixture dominated by hydrated iron oxides, commonly approximated as FeO(OH)·nH₂O
Category: sedimentary
Identified: August 29, 2026
Method: Standard

AI Estimated Value

Typically $1–$15 for a common hand specimen; unusual botryoidal or well-crystallized goethite-rich pieces may bring $20–$100+.

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

Formed when iron-bearing minerals oxidized and hydrated during surface weathering, groundwater alteration, or sediment cementation; such specimens may range from ancient sedimentary deposits to relatively recent weathering rinds. Common in laterite, soil horizons, ironstone beds, and weathered outcrops.

Uses & applications

Used historically as iron ore and as a natural ochre pigment; mostly a teaching or collecting specimen today, with little gemstone value.

Geological facts

Limonite is a field and economic term rather than a single precisely defined mineral. A yellow-brown streak on unglazed porcelain and a strong response to a magnet, if present, can help reveal iron-rich composition.

Field identification & locations

Common worldwide, including Australia, Brazil, India, Africa, and the western United States. Test streak, hardness, density, and acid reaction; laboratory XRD or microscopy is needed to distinguish ironstone from weathered sandstone, goethite, or hematite.