sedimentary

Rounded gray pebble, likely quartz-rich sandstone or chert

Indeterminate lithic clast; possibly quartz arenite (quartz sandstone) or microcrystalline quartz (chert)

AI-generated identification · may be incorrect

Light gray, fine-grained, dull to weakly waxy luster, rounded and water-worn, with faint weathering fractures. Estimated hardness 6–7 if quartz-rich; cleavage absent; specific gravity roughly 2.6.

Identified August 18, 2026More sedimentary →

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At a glance

Common name: Rounded gray pebble, likely quartz-rich sandstone or chert
Scientific name: Indeterminate lithic clast; possibly quartz arenite (quartz sandstone) or microcrystalline quartz (chert)
Category: sedimentary
Identified: August 18, 2026
Method: Standard

AI Estimated Value

Usually $0–$5 as a common pebble; up to about $10–$20 if unusually attractive or confirmed as quality lapidary material.

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

Light gray, fine-grained, dull to weakly waxy luster, rounded and water-worn, with faint weathering fractures. Estimated hardness 6–7 if quartz-rich; cleavage absent; specific gravity roughly 2.6.

Formation & geological history

Likely formed from cemented quartz-rich sediment or silica precipitation, then rounded by stream or beach transport. Its precise geological age and formation environment cannot be determined from the photograph.

Uses & applications

Typically a common landscape, paving, or aggregate stone; attractive pieces may be used as curios or in simple lapidary work, but this specimen has little commercial value.

Geological facts

The smooth shape indicates prolonged abrasion in moving water or surf. A steel nail should not easily scratch a quartz-rich specimen, while a streak test on unglazed ceramic may help distinguish it from softer limestone.

Field identification & locations

Common in streambeds, beaches, gravel deposits, and glacial sediments. Test hardness, acid reaction, grain texture, and a fresh broken surface; identification requires an in-person examination.