Audoliceras Heteromorph Ammonites In Original Quartz Bedrock 345mm [RARE]A fine example of two Audoliceras heteromorph ammonites. Audoliceras were a type of cephalopod that swam in our oceans much like the common squid and modern nautilus. Both ammonites display opalescence and iridescence throughout the nacre of the shell famous characteristics of mineralisation in the Tartar region of Russia. Chitin is a natural element within the shell before the mineralisation process begins which helps this unique effect, caused by