sedimentary

Rounded yellow-brown pebble, likely quartz-rich sandstone or chert

Indeterminate; possible quartz arenite (SiO₂-rich sandstone) or microcrystalline chert

AI-generated identification · may be incorrect

Smooth, water-worn surface; mustard-yellow to tan color with faint mottling and dull to slightly waxy luster. Likely hardness about 6–7 Mohs if quartz-rich; cleavage absent and fracture irregular to conchoidal. Mineral identification is limited by the photograph.

Identified August 19, 2026More sedimentary →

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Physical properties

Formation & geological history

Probably formed from cemented quartz grains or silica-rich sediment, then rounded by stream, beach, or glacial transport; age cannot be determined visually. Iron-oxide staining likely produces the yellow-orange color.

Uses & applications

Common specimens have little commercial value, though sandstone is used for aggregate and building stone, while chert is used for tools and landscaping.

Geological facts

The uniformly smooth, rounded shape indicates substantial transport or abrasion. A steel nail should not scratch quartz-rich material, while a knife may leave a mark on softer sandstone.

Field identification & locations

Check texture with a hand lens: visible sand grains suggest sandstone; a very uniform, glassy or waxy interior suggests chert. Common worldwide; estimated value is $0–$5 as an ordinary pebble, or roughly $5–$20 if unusually attractive or polished.