This is such a nice split set. The colors are rich and vibrant and chambers are large, well defined and full of quartz and calcite. This is one fossil, split in half and polished to reveal the hidden living chambers that once housed a predatory mullusk. Ammonites were predators that resembled a squid with a shell. These cephalopods had eyes, tentacles, and spiral shells. They are more closely related to a living octopus, though the shells resemble that of a nautilus.