Sawn calcified ammonite with chambers

Calcified chambered ammonite is a fossil of a cephalopod that lived in the Mesozoic seas, a period spanning approximately 252 to 66 million years ago. This specimen has been cut in half to reveal its characteristic internal chambers, often preserved through the process of mineralization. The color and texture vary depending on the mineral composition and fossilization conditions. These fossils come from Madagascar, generally from regions that were once underwater where they were deposited on the bottom of ancient seas.