This is an authentic Ammonite and sterling silver ring. The size of the ring is 9 and the size of the Ammonite is 2" x 1.5". Ammonites are an extinct group of marine invertebrate animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs are more closely related to living coleoids (i.e. octopuses, squid, and cuttlefish) than they are to shelled nautiloids such as the living Nautilus species.