fossil

Trilobite Fossil in Limestone

Trilobita (Class), likely embedded in fossiliferous limestone (CaCO3)

AI-generated identification · may be incorrect

Hardness: 3-4 (matrix); Color: Gray to blue-gray; Luster: Dull to earthy; Texture: Fine-grained with visible segmented anatomical details of the exoskeleton.

Hardness: 3-4 (matrix)
Color: Gray to blue-gray
Luster: Dull to earthy

Identified July 4, 2026More fossil →

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Physical properties

Hardness: 3-4 (matrix); Color: Gray to blue-gray; Luster: Dull to earthy; Texture: Fine-grained with visible segmented anatomical details of the exoskeleton.

Formation & geological history

Formed during the Paleozoic Era (approx. 400-500 million years ago) in a shallow marine environment where the exoskeleton was buried in carbonate mud.

Uses & applications

Educational study, paleontological research, and as a collector's specimen.

Geological facts

Trilobites were among the most successful of all early animals, roaming the oceans for over 270 million years before going extinct during the Permian extinction. The location near Louisville, KY is famous for the Falls of the Ohio, a massive fossilized Devonian coral reef.

Field identification & locations

Identified by the distinct segmented lobes (three-lobed body). In the field, look for symmetrical patterns in sedimentary rocks like limestone or shale. This specimen matches the Ordovician-Devonian geology of the Kentucky/Indiana border.