sedimentary

Layered shale or mudstone fragment

Fissile claystone/mudstone, commonly clay minerals with quartz and minor iron oxides

AI-generated identification · may be incorrect

Fine-grained, thinly bedded and strongly fissile, with brown-gray weathering and dull earthy luster; typical hardness is about 2–3 Mohs, with no visible crystals or cleavage faces.

Identified August 14, 2026More sedimentary →

Explore Layered shale or mudstone fragment in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Fine-grained, thinly bedded and strongly fissile, with brown-gray weathering and dull earthy luster; typical hardness is about 2–3 Mohs, with no visible crystals or cleavage faces.

Formation & geological history

Formed when clay- and silt-rich sediment compacted and lithified in quiet-water settings such as lakes, floodplains, or marine basins; its age cannot be determined from the photograph and may range from Paleozoic to recent geological formations.

Uses & applications

Used locally as fill or aggregate and, where thick and suitable, as a source of brick, cement, or roofing slate; ordinary fragments have negligible jewelry value.

Geological facts

The parallel layers represent original sedimentary bedding, while the easy splitting reflects fissility produced during compaction and weak mineral alignment.

Field identification & locations

Identify it by fine texture, planar layers, earthy color, and splitting into thin sheets; distinguish it from slate by its softer, less polished surfaces and lack of strong metamorphic cleavage. Common worldwide in sedimentary basins.