sedimentary

Shale with Trace Fossils

Fissile mudrock (Shale)

Hardness: 3 on Mohs scale; Color: Gray, brown, and tan; Luster: Dull/Earthy; Structure: Clastic, fine-grained, showing fissility (layering); Specific Gravity: 2.2-2.8

Hardness: 3 on Mohs scale
Color: Gray, brown, and tan
Luster: Dull/Earthy

Identified July 6, 2026More sedimentary →

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Physical properties

Hardness: 3 on Mohs scale; Color: Gray, brown, and tan; Luster: Dull/Earthy; Structure: Clastic, fine-grained, showing fissility (layering); Specific Gravity: 2.2-2.8

Formation & geological history

Formed through the lithification of mud, clay, and silt-sized particles deposited in slow-moving water environments like lake beds or deep ocean floors over millions of years.

Uses & applications

Primarily used in the production of cement, bricks, and as a raw material for the ceramics industry. Can be a source of natural gas or oil.

Geological facts

Shale is the most common sedimentary rock on Earth, making up approximately 70% of the sedimentary rocks in the crust. It often contains well-preserved fossils due to the fine-grained nature of its sediment.

Field identification & locations

Identify in the field by its thin layers (fissility) and tendency to break into flat planes. Found globally in basins. This specimen shows dark mineralized impressions that may be carbonaceous remains or trace fossils.