2.5" Iridescent, Pyritized Ammonite (Quenstedticeras) Fossil - Russia
This is a gorgeous pyritized ammonite of the genus Quenstedticeras. It was collected from a Middle Jurassic age deposit along the banks of the Volga River near Saratov, Russia. You can feel the heft of the iron pyrite in the specimen when you hold it in your hand. When rotating the fossil under a light source, the shell exhibits a brilliant iridescence.
Ammonites 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. True ammonites appeared in the fossil record about 240 million years ago. The last lineages disappeared 65 million years ago at the end of the Cretaceous.