sedimentary

Weathered quartz-rich cobble (probable sandstone or quartzite)

Indeterminate; likely quartz arenite sandstone, possibly weakly metamorphosed quartzite

AI-generated identification · may be incorrect

Rounded, yellow-brown and fine-grained, with dull to subtly sparkling luster and apparent quartz-rich texture; individual grains are poorly resolved. Estimated hardness 6–7 Mohs, no obvious cleavage, and moderate-to-high density.

Identified September 17, 2026More sedimentary →

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At a glance

Common name: Weathered quartz-rich cobble (probable sandstone or quartzite)
Scientific name: Indeterminate; likely quartz arenite sandstone, possibly weakly metamorphosed quartzite
Category: sedimentary
Identified: September 17, 2026
Method: Standard

AI Estimated Value

$0–$10 as an ordinary collected cobble; approximately $10–$30 if unusually attractive, polished, or sold as a labeled specimen.

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 a water-worn river or beach cobble, stained by iron oxides during weathering. If sandstone, it formed from cemented quartz sand; if quartzite, recrystallization occurred during metamorphism, generally at least hundreds of millions of years ago.

Uses & applications

Commonly used as landscaping or decorative stone; not typically suitable for jewelry unless cut and polished. Market value is usually minimal.

Geological facts

The ochre coloration most likely comes from limonite/goethite coatings rather than the primary rock minerals. The photograph cannot reliably distinguish sandstone from quartzite.

Field identification & locations

Look for visible sand grains and grain boundaries: gritty, easily scratched grains suggest sandstone; fused interlocking quartz and very high toughness suggest quartzite. Common in river gravels, beaches, and weathered outcrops.