2.3" Translucent Ammonite (Asteroceras) Fossil - Dorset, England
This is a beautifully prepared, 2.3" wide Asteroceras obtusum ammonite fossil from the Lyme Regis region of England. Most of the shell is preserved as a translucent, yellow calcite. During preparation the rock has been removed from behind the ammonite so that it can be back-lit with a light source causing it to glow. The surrounding limestone has been aesthetically sculpted into it's own display base.
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.