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

Trilobite Fossil

Phylum Arthropoda, Subphylum Trilobita

AI-generated identification · may be incorrect

Hardness varies by mineral replacement (typically Mohs 3-5); colors range from grey and brown to black; luster is earthy to vitreous; exhibits a distinct three-lobed, segmented exoskeleton.

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Physical properties

Hardness varies by mineral replacement (typically Mohs 3-5); colors range from grey and brown to black; luster is earthy to vitreous; exhibits a distinct three-lobed, segmented exoskeleton.

Formation & geological history

Formed during the Paleozoic Era (Cambrian to Permian periods, roughly 521 to 252 million years ago) through the rapid burial and fossilization of marine arthropods in fine-grained sediment.

Uses & applications

Prized by paleontologists for biostratigraphy and widely collected by fossil enthusiasts for display and educational purposes.

Geological facts

Trilobites are one of the earliest well-known groups of arthropods and possessed some of the first complex eyes in the animal kingdom.

Field identification & locations

Found worldwide in sedimentary marine shales and limestones; identify by searching for the characteristic segmented head, thorax, and pygidium in split rock layers.

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

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Bioclastic limestone, composed chiefly of calcite (CaCO₃)

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