sedimentary

Rounded sedimentary pebble, likely mudstone or shale

Argillite/mudstone; predominantly compacted clay minerals with quartz and iron oxides

AI-generated identification · may be incorrect

Gray-tan, fine-grained, dull to earthy luster, with thin layered or platy structure and rounded weathered edges. Likely Mohs hardness 2–4; cleavage or splitting may follow bedding; specific gravity about 2.3–2.7.

Identified August 10, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed from compacted and lithified clay-rich sediment in a quiet-water basin, commonly millions to hundreds of millions of years old; exact age cannot be determined from the photograph.

Uses & applications

Used locally as fill, landscaping stone, or aggregate; attractive pieces may be collected, but it is generally unsuitable for jewelry except as a polished novelty stone.

Geological facts

The visible parallel layers and muted gray-brown color are consistent with shale or mudstone, though the image cannot distinguish these confidently from a weathered fine-grained metamorphic rock.

Field identification & locations

Look for very fine grains, bedding, earthy surfaces, and splitting into thin layers; a streak, hardness, and fresh broken surface would improve identification. Common worldwide in sedimentary basins.