What's That Rock?

Trilobite

Fossil

An extinct sea creature with a three-lobed body, an arthropod, a distant relative of crabs and insects. Trilobites lived from about 520 to 250 million years ago.

How to identify Trilobite

  1. Three lengthwise sections and a segmented body
  2. A head shield, a body of segments and a tail shield
  3. Usually found curled or flat in shale or limestone

Often confused with

  • Leaf impressions
  • Insect-like concretions
  • Carved or composite fakes

Real or fake?

  • Many Moroccan trilobites are partly or fully carved or put together from pieces; look for glue lines and mismatched stone
  • Heavily 'perfect' specimens at low prices are suspect

Is Trilobite valuable?

Common types are inexpensive; rare, large or perfectly preserved specimens cost more.

Typical retail prices

Collector specimen$15–200each

Typical retail ranges in US dollars, compiled from public dealer and marketplace listings in October 2026. Real prices vary widely with quality, size and origin. This is general information, not an appraisal.

What changes the price

  • Species and completeness: a complete, enrolled or large specimen with a visible eye costs far more than a fragment
  • Preparation: skillful cleaning matters, but 'composite' pieces assembled from different fossils are sold as natural
  • Origin: Moroccan, Utah and Ohio trilobites vary, and rare species cost much more
  • Legal source: some sites restrict collecting

Uses

  • Collecting and display

Care

Fragile. Keep away from water and knocks.

Identifying a stone from a description or a photo is an estimate. Many stones look alike. Ask an expert or a gem lab before you buy, sell or rely on an identification.

Updated October 2026