sedimentary

Weathered iron-rich sandstone or ironstone cobble

Ferruginous sandstone/ironstone, chiefly quartz (SiO₂) cemented or stained by iron oxides and hydroxides

AI-generated identification · may be incorrect

Typically Mohs hardness 5–7, dull to earthy luster, tan-brown to reddish coloration, and irregular fractures; visible layering or rounded weathering may occur. Exact mineralogy cannot be confirmed from a photograph alone.

Identified August 8, 2026More sedimentary →

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At a glance

Common name: Weathered iron-rich sandstone or ironstone cobble
Scientific name: Ferruginous sandstone/ironstone, chiefly quartz (SiO₂) cemented or stained by iron oxides and hydroxides
Category: sedimentary
Identified: August 8, 2026
Method: Standard

AI Estimated Value

About $5–$30 for a common specimen; roughly $30–$100 if unusually patterned, locality-documented, or fossil-bearing.

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-rich sand was cemented and later enriched by hematite, limonite, or goethite in an oxidizing groundwater environment; age depends on locality and may range from Paleozoic to Cenozoic.

Uses & applications

Commonly used as decorative or landscaping stone, aggregate, and occasionally building stone; attractive pieces may be collected, though this specimen appears primarily natural and non-gem quality.

Geological facts

Iron staining can produce purple, yellow, brown, and red patches, while weathering may create convoluted surface patterns that resemble fossils or carvings.

Field identification & locations

Look for gritty texture, quartz grains, earthy iron staining, and a relatively high weight; a streak, hardness, and acid test would help distinguish it from claystone or altered volcanic rock. Common in continental sedimentary terrains and iron-rich soils.