This Specimen has been sold.
3.5 Inch Polished Madagascar Ammonite (Half)
Here is a 110 million year old ammonite fossil from Madagascar which has been sliced in half and polished. The chambers of the ammonite have been agatized and some of them are filled with pockets of calcite crystals.
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. 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.