fossil

Fossiliferous Shale

Sedimentary Clastic Rock with fossil inclusions (likely Brachiopod or Bivalve impressions)

AI-generated identification · may be incorrect

Hardness: 3-5 on Mohs scale; Color: Dark gray, bluish-gray, to brownish; Luster: Dull/Earthy; Structure: Fine-grained, fissile (layers visible); Cleavage: Perfect along bedding planes.

Hardness: 3-5 on Mohs scale
Color: Dark gray, bluish-gray, to brownish
Luster: Dull/Earthy

Identified July 15, 2026More fossil →

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Physical properties

Hardness: 3-5 on Mohs scale; Color: Dark gray, bluish-gray, to brownish; Luster: Dull/Earthy; Structure: Fine-grained, fissile (layers visible); Cleavage: Perfect along bedding planes.

Formation & geological history

Formed from the compaction of silt and clay-sized mineral particles in low-energy aquatic environments such as lake bottoms or deep ocean basins. The visible curved markings are impressions of ancient marine life, likely Paleozoic in age (250-500 million years old).

Uses & applications

Primarily used for geological study, education, and as collector specimens. Large scale shale is used in the production of cement and bricks.

Geological facts

Shale is the most common sedimentary rock on Earth. The markings on this specimen appear to be partial brachiopod shell impressions, which are among the most common fossils found in marine sedimentary layers.

Field identification & locations

Identify by its gray color, fine texture, and ability to split into thin sheets. Look for curved, symmetrical impressions of shells. Commonly found in riverbeds, cliffs, and quarries in regions with sedimentary basin history.