Rock Identifier
Trilobite Fossil (Phylum Arthropoda, Class Trilobita) — fossil
fossil

Trilobite Fossil

Phylum Arthropoda, Class Trilobita

AI-generated identification · may be incorrect

Hardness varies by mineral replacement (often calcite, Mohs 3); color ranges from grey to brown; exhibits segmented exoskeleton structure with distinct cephalon, thorax, and pygidium.

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Physical properties

Hardness varies by mineral replacement (often calcite, Mohs 3); color ranges from grey to brown; exhibits segmented exoskeleton structure with distinct cephalon, thorax, and pygidium.

Formation & geological history

Formed through permineralization in ancient Paleozoic marine environments, dating from approximately 521 to 252 million years ago.

Uses & applications

Valued by fossil collectors, used in paleontological research, and displayed as educational or decorative specimens.

Geological facts

Trilobites are among the most successful early animals, existing for over 270 million years before going extinct in the Permian-Triassic extinction event.

Field identification & locations

Found worldwide in sedimentary rock layers, particularly shale and limestone; identify by looking for their distinctive three-lobed, segmented body shape.

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Fossiliferous limestone (likely a crinoidal or shell-fragment limestone) (Bioclastic limestone, composed chiefly of calcite (CaCO₃)) — sedimentary

Fossiliferous limestone (likely a crinoidal or shell-fragment limestone)

Bioclastic limestone, composed chiefly of calcite (CaCO₃)

sedimentary
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Porous limestone pebble

Calcite-rich limestone (primarily CaCO₃); exact identification is uncertain from the image

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Weathered fossil bone fragment (identification uncertain)

Fossilized bone; exact taxon and mineral composition cannot be determined from the image

fossil