This ammonite is split in half and is polished on the inside. It's approximate measurements are 92 x 113 mm: thickness 29 mm: weight is 337 grams
 
Ammonites were Marine animals that belonged to the Cephalopods. They had coils shells like the nautilus. They appeared 425 million years ago and were common in the oceans when the dinosaurs were alive. They went extinct some 66 million years ago.