This is a beautiful, cut and polished ammonite of the genus Desmoceras from Madagascar. These ammonites are much thicker and heaver than the more commonly seen Cleoniceras ammonites. They are middle Cretaceous in age, approximately 110 million years old. Many of the chambers have been preserved as beautiful crystal lined pockets.
These ammonites come with acrylic display stands.
were predatory mollusks 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. Ammonites appeared in the fossil record about 240 million years ago and they barely survived several major extinction events. The last lineages disappeared 65 million years ago at the end of the Cretaceous.
Artists reconstruction of an ammonite. By Nobu Tamura