Ammonites were a group of molluscs living in the sea, and related to the present squid. Nowadays, these animals have their shells inside, but the Ammonites had their shell still outside the body, like snails.
The ammonite is approximately 112 million years old and completely fossilized. This piece has been cut and polished. As a result, the different rooms are beautifully visible. The two halves together form a pair and give a beautiful view of how the ammonite, by extending its shell, continued to grow with one room at a time.
Fossil ammonite from Madagascar
The most beautiful ammonites are found in Madagascar and can have dimensions up to 25 centimeters in diameter. This ammonite belongs to the family of the Cleoniceras. In some hollow rooms calcite crystals are visible. These are actually crystal geodes inside the fossil. Ammonites got extinct like the dinosaurs about 65 million years ago.