Ammonites, polished and cut
Ammonites were a group of marine molluscs that also included the current squid. Nowadays these animals have their shell on the inside, but the Ammonites still had their shell outside the body, just like snails.
The Cleoniceras ammonites from Madagascar are one of the most beautiful. The exterior has a layer of opal with beautiful shades of colour and often the stitches are also visible. Cut through, this ammonite shows in a spectacular way the different chambers that are filled with calcite. In some cases even a small geode has been created in it. This ammonite species lived in albien and about 110 million years old.
These special ammonites from Madagascar have the nice nickname: 'tractor ammonites'. The thick ribs on the ammonite are reminiscent of tractor tyres. These ammonites lived around the same time as the Cleoniceras ammonites in the under cretaceous and are about 112 million years old. These ammonites are completely fossilized in calcite and polished to show the beautiful colors, ripples and sutures.
Ammonites in general
Ammonites were cephalopods and are related to the current squid and nautilus. Ammonites died out 65 million years ago together with the dinosaurs. The ammonite always lived in the largest room of the shell and built up an extra chamber when it became too small.