sedimentary

Weathered sandstone or iron-rich sedimentary cobble

Quartz arenite to ferruginous sandstone; predominantly SiO₂ (quartz) with iron-oxide cement

AI-generated identification · may be incorrect

Likely Mohs hardness 6–7 for quartz grains but friable overall; reddish-brown, dull to earthy luster, fine- to medium-grained, with irregular pits and possible weathering cavities. No obvious cleavage; specific gravity approximately 2.2–2.7.

Identified August 11, 2026More sedimentary →

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At a glance

Common name: Weathered sandstone or iron-rich sedimentary cobble
Scientific name: Quartz arenite to ferruginous sandstone; predominantly SiO₂ (quartz) with iron-oxide cement
Category: sedimentary
Identified: August 11, 2026
Method: Standard

AI Estimated Value

About $1–$20 as an ordinary found cobble; up to $20–$100 if unusually attractive, fossil-bearing, or provenance-specific.

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 sand accumulated, compacted, and cemented, with iron oxides producing the reddish color; later rounded and weathered in a river, beach, or glacial environment. Exact age cannot be determined from the image.

Uses & applications

Used as building stone, paving, aggregate, and occasionally decorative or landscaping stone; generally little jewelry value.

Geological facts

The smooth, rounded shape suggests transport abrasion, while the holes may reflect differential weathering of softer grains or embedded pebbles. A weak acid reaction would indicate carbonate cement, but quartz-rich sandstone usually does not fizz.

Field identification & locations

Common in sedimentary basins and gravel deposits worldwide; inspect fresh broken surfaces for visible sand grains and layering, and test streak, hardness, and acid reaction. The image alone cannot distinguish sandstone confidently from weathered siltstone or iron-rich volcanic rock.