Trilobite Fossil

Physical Properties

Hardness: 3-4 (matrix usually limestone or shale); Color: Brownish to grey; Luster: Variable, often dull but can be vitreous; Structure: Symmetrical three-lobed exoskeleton of calcified chitin.

Formation & Geological History

Formed through permineralization in marine environments during the Paleozoic era, roughly 521 to 252 million years ago. Usually found in shale, siltstone, or limestone matrix.

Uses & Applications

Primarily used for scientific research, educational purposes, and by hobbyist collectors.

Geological Facts

Trilobites are one of the earliest known groups of arthropods and survived for nearly 300 million years through multiple mass extinction events before finally going extinct in the Permian period.

Field Identification & Locations

Identify by looking for the distinct cephalon (head), thorax (segmented body), and pygidium (tail) segments. Commonly found in quarries and road cuts with exposed Paleozoic strata.

Identified on: 5/2/2026

Mode: Standard