sedimentary

Iron-stained sandstone or weathered ironstone concretion

Quartz-rich sandstone, locally cemented by iron oxides (hematite/goethite); exact identification requires testing

AI-generated identification · may be incorrect

Tan to rusty brown, earthy surface, dull to weakly vitreous luster, granular texture, and irregular fractures; quartz gives Mohs hardness about 7, while iron-oxide coatings are softer. No obvious cleavage or crystal faces; the rounded shape suggests abrasion or concretionary growth.

Identified August 10, 2026More sedimentary →

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At a glance

Common name: Iron-stained sandstone or weathered ironstone concretion
Scientific name: Quartz-rich sandstone, locally cemented by iron oxides (hematite/goethite); exact identification requires testing
Category: sedimentary
Identified: August 10, 2026
Method: Standard

AI Estimated Value

About $5-$25 for a common hand specimen; potentially $25-$75 if unusually shaped, fossiliferous, or from a documented locality.

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 when quartz sand was compacted and cemented, with later groundwater oxidation producing hematite/goethite staining. Such rocks commonly formed in continental or shallow-marine sedimentary environments over millions to hundreds of millions of years.

Uses & applications

Used locally as building or landscaping stone and collected as a natural specimen; this example has little gem or industrial value.

Geological facts

The bright yellow-orange areas may contain goethite or limonite, while darker red-brown zones commonly indicate hematite. A streak test and acid test can help distinguish ironstone from carbonate-rich rock.

Field identification & locations

Common in weathered sedimentary terrains worldwide, including Australia, India, Africa, and the western United States. A glass scratch test, gritty texture, and reddish-yellow streak support sandstone/ironstone identification; visible fossils or strong fizzing would suggest alternatives.