sedimentary

Rounded river cobble, likely weathered sandstone or quartz-rich metasandstone

Indeterminate sandstone; commonly quartz (SiO₂) with feldspar, lithic grains, and iron-oxide cement

AI-generated identification · may be incorrect

Fine-grained, tan-gray, dull to slightly earthy luster, and strongly rounded by abrasion; apparent hardness roughly 5–7 depending on cement, with no visible cleavage or crystals. The orange-brown coloration likely reflects iron-oxide staining.

Identified August 7, 2026More sedimentary →

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At a glance

Common name: Rounded river cobble, likely weathered sandstone or quartz-rich metasandstone
Scientific name: Indeterminate sandstone; commonly quartz (SiO₂) with feldspar, lithic grains, and iron-oxide cement
Category: sedimentary
Identified: August 7, 2026
Method: Standard

AI Estimated Value

Typically $1–$10 as a common cobble; perhaps $10–$30 if locally distinctive, unusually attractive, or provenance 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 from compacted and cemented sand, then transported and polished in a river, beach, or glacial environment. Its depositional age cannot be determined from the image.

Uses & applications

Usually used as a landscape or decorative stone, garden cobble, paperweight, or specimen; it has little industrial or jewelry value unless composition proves unusual.

Geological facts

The smooth elliptical shape records prolonged mechanical abrasion and preferential wear. A streak, acid, and fresh-surface examination would help distinguish sandstone from quartzite or a volcanic rock.

Field identification & locations

Common in river gravels and shorelines worldwide; identify by testing grain texture, hardness, and porosity—sandstone feels granular and may scratch glass variably, whereas quartzite is very hard and resists scratching. Exact classification requires a fresh fracture or thin section.