What are ammonites?
Ammonites were a group of marine mollusks that include today's squid. Today, these animals have their shells inside, but the Ammonites still had their shells outside the body, just like snails. The ammonite is about 112 million years old and completely fossilized. This copy has been polished. As a result, the sutures that gave chambers strength are nicely visible.
Fossil ammonite from Madagascar
The most beautiful ammonites are found in Madagascar and can measure up to 25 centimeters in diameter. This ammonite belongs to the Cleoniceras family. Calcite crystals occur in some hollow chambers. These are actually crystal geodes inside the fossil. Ammonites, like the dinosaurs, died out about 65 million years ago.