sedimentary

Weathered shale or mudstone

Fine-grained clastic sedimentary rock, predominantly clay minerals and silt-sized quartz

AI-generated identification · may be incorrect

Brown to tan, dull, and visibly layered or fissile; typically Mohs hardness 2–3. Individual grains are too small to identify in this image, and the wet surface makes luster and texture less certain.

Identified October 14, 2026More sedimentary →

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Physical properties

Formation & geological history

Forms when clay and fine silt settle in quiet water, then compact and cement into rock. Its age cannot be determined from the photograph; shale and mudstone form in environments ranging from ancient lake beds to marine basins.

Uses & applications

Commonly used as fill and aggregate; clay-rich varieties are raw material for cement and some bricks. This rough specimen has little jewelry or collector value.

Geological facts

Shale splits into thin sheets more readily than mudstone, though weathering can obscure the distinction.

Field identification & locations

The apparent layering and fine-grained, earthy surfaces suggest shale or mudstone, but the image is not enough to confirm the rock type. These rocks occur widely in sedimentary basins; a fresh, dry surface and a close view of layering would help identification.