These first emerged in the early Cambrian period approximately 500 million years ago and lived for nearly 350 million years until the Jurassic period. They lived throughout the world with strong concentrations in the mid-western United States. The name "Trilobite" stems from the characteristic three segments that comprise each animal's body. Trilobites ranged in size from ¼" to giant specimens to 2 feet long. They were the first insects to have eyesight.  It comes with a Certificate of Authenticity and a story booklet. The rock measures about 3½" and the fossil itself is about ¾" in length.  It was found in the USA.