sedimentary

Weathered iron-rich limestone or sandstone

Ferruginous carbonate/siliciclastic rock; likely calcite- and iron-oxide-bearing matrix

AI-generated identification · may be incorrect

Tan to gray, porous and strongly weathered, with rusty yellow-brown iron staining and possible dark manganese or organic bands. Likely hardness about 3–6 depending on calcite versus quartz content; dull to earthy luster, no obvious crystal faces or cleavage visible.

Identified August 14, 2026More sedimentary →

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At a glance

Common name: Weathered iron-rich limestone or sandstone
Scientific name: Ferruginous carbonate/siliciclastic rock; likely calcite- and iron-oxide-bearing matrix
Category: sedimentary
Identified: August 14, 2026
Method: Standard

AI Estimated Value

About $5–$25 as a common hand specimen; higher only if locality, unusual mineralization, or strong fossil content is 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

Probably formed as carbonate or sand-rich sediment that lithified and later underwent groundwater oxidation, producing limonite/goethite staining. Its exact geological age and formation environment cannot be determined reliably from the photograph alone.

Uses & applications

Primarily a geological or landscaping specimen; comparable rock may be used as aggregate, building stone, or cement feedstock if sufficiently sound, though this piece appears too weathered for structural use.

Geological facts

The vivid rusty coloration commonly reflects hydrated iron oxides such as limonite and goethite filling pores and fractures. Yellow streaks may also indicate sulfur-bearing alteration, but testing is needed.

Field identification & locations

Look for a weak fizz with dilute hydrochloric acid or vinegar if calcite-rich, and a glassy fracture or gritty texture if quartz-rich; a steel nail helps estimate hardness. Common in weathered sedimentary outcrops and iron-rich zones worldwide.