sedimentary

Shale (or Mudstone)

Laminose Mudrock (composition: clay minerals, quartz, and mica flakes)

AI-generated identification · may be incorrect

Hardness: 3 on Mohs scale; Color: Gray, brown, or charcoal; Luster: Dull/Earthy; Structure: Clastic with visible fissility (splitting into thin layers); Cleavage: Perfect along bedding planes.

Hardness: 3 on Mohs scale
Color: Gray, brown, or charcoal
Luster: Dull/Earthy

Identified July 15, 2026More sedimentary →

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Physical properties

Hardness: 3 on Mohs scale; Color: Gray, brown, or charcoal; Luster: Dull/Earthy; Structure: Clastic with visible fissility (splitting into thin layers); Cleavage: Perfect along bedding planes.

Formation & geological history

Formed through the lithification of clay and silt-sized particles deposited in slow-moving water environments like floodplains, lagoons, or deep ocean basins. Generally found in Paleozoic to Cenozoic sedimentary basins.

Uses & applications

Raw material for the production of brick, tile, and cement. Often serves as a source or reservoir rock for natural gas and petroleum (shale gas).

Geological facts

Shale accounts for approximately 70% of the sedimentary rock in the Earth's crust. It is the most common rock involved in the hydraulic fracturing process for energy extraction.

Field identification & locations

Identify by its ability to split into thin, flat sheets (fissility) and its soft, clay-like texture when wet. Commonly found in road cuts or stream banks in regions with sedimentary bedrock.