sedimentary

Shale (possibly Carbonaceous or Oil Shale)

Laminated Mudstone (primarily clay minerals and quartz)

AI-generated identification · may be incorrect

Hardness: 3-4 (Mohs); Color: Black to dark gray; Luster: Dull/Earthy; Structure: Fissile/Laminated; Cleavage: Basal (splits into thin sheets); Specific Gravity: 2.2-2.8

Hardness: 3-4 (Mohs)
Color: Black to dark gray
Luster: Dull/Earthy

Identified June 8, 2026More sedimentary →

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Physical properties

Hardness: 3-4 (Mohs); Color: Black to dark gray; Luster: Dull/Earthy; Structure: Fissile/Laminated; Cleavage: Basal (splits into thin sheets); Specific Gravity: 2.2-2.8

Formation & geological history

Formed through the compaction of silt and clay-sized mineral particles over millions of years in low-energy environments like lake beds or deep ocean floors. Black varieties indicate high organic content.

Uses & applications

Used in the production of bricks, cement, and pottery. Bituminous shale can be a source of oil and natural gas (fracking industry).

Geological facts

Shale is the most common sedimentary rock on Earth, making up an estimated 70% of the rocks in the Earth's crust. It often preserves fossils because of the fine sediment size.

Field identification & locations

Identify by its tendency to split into thin layers (fissility) and its soft, earthy texture. It is commonly found in basins and river deltas worldwide.