sedimentary

Weathered rounded cobble

Indeterminate lithology; likely weathered sandstone or volcanic rock

AI-generated identification · may be incorrect

Hardness approximately 5–7 Mohs; tan-gray, fine-grained, dull to slightly earthy luster, massive texture, and no visible cleavage. Its smooth, flattened shape reflects abrasion rather than crystal structure.

Identified August 21, 2026More sedimentary →

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Physical properties

Formation & geological history

Likely a fluvial or glacial cobble transported and rounded by moving water or ice; its exact age and parent formation cannot be determined from the image. The surrounding dark gravel suggests a mixed alluvial deposit.

Uses & applications

Primarily a natural landscape or collecting specimen; stones of this type may be used decoratively, in landscaping, or as aggregate, but this example has little commercial value.

Geological facts

The orange-brown surface coloration commonly results from iron-oxide weathering. Its shape indicates prolonged transport or wave abrasion.

Field identification & locations

Identify it by its rounded outline, weathered rind, massive fine-grained appearance, and lack of obvious layering or crystals; a fresh broken surface and acid, streak, or hardness tests would be needed for precise identification. Common in streambeds, beaches, glacial deposits, and gravel bars.