This Specimen has been sold.
2" Iridescent Fossil Ammonite (Phylloceras) - Madagascar
This is a 2" fossil ammonite (Phylloceras) from the Mahajanga Province of Madagascar. If you catch it in the right light or particularly if it is wet, the fossil shines with 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.