Beautiful whole polished ammonite from Madagascar. this large piece has really nice suture pattern and an opalized center. Ammonites are perhaps the most widely known fossil, possessing the typically ribbed spiral-form shell. These creatures lived in the seas between 240 - 65 million years ago, when they became extinct along with the dinosaurs. The name 'ammonite' originates from the Greek Ram-horned god called Ammon. Ammonites belong to a group of predators known as cephalopods, which includes their living relatives the octopus, squid, cuttlefish and nautilus.