(1) Authentic Mid-grade Calymine Trilobite from Morocco. Each specimen will measure 2-4 inches in length. Each trilobite will come with an information card to learn about trilobites! These trilobites are from the late Ordovician period, meaning they are 461 to 444 million years old! Please note these are completely authentic and natural specimens. Each trilobite will be slightly different in shape, color, size, and overall appearance. Some of these trilobites may have been glued back together as they are commonly found in pieces. These are mid-grade specimens, meaning most have multiple s, have been glued, or are somehow damaged.