This cast was taken from a genuine fossilized Pleuroceras Ammonite negative. A mold was made in wax, then hand carved into this small, round shape. Negative fossils are a trace fossil that are made when an ammonite shell was pressed into sediment, leaving an impression. That sediment eventually fossilized. The specimen used to create this piece came from Germany and dates to the Lower Jurassic, about 185 million years ago!