3.7 Inch Polished Madagascar Ammonite (Half)

Inch Polished Madagascar Ammonite (Half) #886

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 squids with shells. These cephalopods had eyes, tentacles, and spiral shells. Though their shells resemble that of a nautilus, they are actually more closely related to living octopuses. Ammonites appeared in the fossil record about 240 million years ago, barely surviving several major extinction events. The last lineages disappeared 65 million years ago at the end of the Cretaceous.

Artist's reconstruction of an ammonite, by Nobu Tamura

More about ammonites