2.1" Pyrite Encrusted Ammonite Fossil - Russia
This is a pyritized ammonite fossil that is encrusted in pyrite, collected from a Middle Jurassic deposit along the banks of the Volga River near Saratov, Russia. You can feel the heft of the iron pyrite in and on the specimen when you hold it in your hand.
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.