sedimentary

Fossiliferous Shale

Carbonaceous Shale (with potential plant/aquatic fossils)

AI-generated identification · may be incorrect

Hardness: 3 (Mohs scale), Color: Dark grey to black, Luster: Dull/Earthy, Crystal structure: Fine-grained/Aphanitic, Cleavage: Fissile (splits into layers)

Identified June 19, 2026More sedimentary →

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Physical properties

Hardness: 3 (Mohs scale), Color: Dark grey to black, Luster: Dull/Earthy, Crystal structure: Fine-grained/Aphanitic, Cleavage: Fissile (splits into layers)

Formation & geological history

Formed in low-energy environments like lake bottoms, swamps, or deep ocean floors through the compaction of clay and organic matter. This specimen appears to contain organic imprints characteristic of the Paleozoic or Mesozoic eras.

Uses & applications

Primary source for oil and natural gas (oil shale), used in the manufacture of brick, tile, and Portland cement. Frequently collected by paleontologists.

Geological facts

Dark shale gets its color from high organic content (carbon). It is the most common sedimentary rock on Earth and often preserves delicate fossils that would be destroyed in more turbulent environments.

Field identification & locations

Identify by its dark color, fine grain, and tendency to flake into flat sheets. Look for textural anomalies on the surface that may indicate fossilized organic remains like leaves or shells.