sedimentary/metamorphic

Rounded beach pebbles, likely quartz-rich sandstone and weathered quartzite

Quartz-rich sandstone (SiO₂-bearing) and possible quartzite; exact identification requires testing

AI-generated identification · may be incorrect

Gray to tan, fine-grained, dull to weakly silky surfaces with rounded water-worn shapes; chiefly quartz with possible feldspar and cement. Hardness likely 6–7 Mohs, no obvious cleavage, and moderate-to-high density.

Identified August 23, 2026More sedimentary/metamorphic →

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At a glance

Common name: Rounded beach pebbles, likely quartz-rich sandstone and weathered quartzite
Scientific name: Quartz-rich sandstone (SiO₂-bearing) and possible quartzite; exact identification requires testing
Category: sedimentary/metamorphic
Identified: August 23, 2026
Method: Standard

AI Estimated Value

$0–$5 each as common pebbles; approximately $5–$20 for unusually attractive polished or display specimens.

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

These are naturally rounded clasts formed by erosion and abrasion in a stream, beach, or gravel deposit; sandstone lithified during the Paleozoic–Cenozoic, while quartzite formed when sandstone was metamorphosed. The image alone cannot establish a precise age or composition.

Uses & applications

Commonly used for landscaping, garden decoration, crafts, and educational collections; attractive pieces may be polished, but these specimens have little jewelry value.

Geological facts

The smooth edges indicate prolonged transport or wave action. A glass-scratch test and dilute acid test can help distinguish quartzite from carbonate-rich rocks.

Field identification & locations

Likely locations include riverbeds, beaches, glacial gravels, and landscaping gravel. Quartz-rich stones scratch ordinary glass; sandstone feels granular and may shed grains, whereas quartzite is harder and more fused.