How does ammonite become fosilised?

Ammonites become fossilized through a process called permineralization, where minerals from surrounding sediments seep into the empty spaces within the ammonite shell after it has died. Over time, these minerals crystallize, preserving the intricate details of the shell. Conditions such as rapid burial and anoxic environments (low oxygen) help prevent decomposition, allowing for effective fossilization. Ultimately, the organic material decays, leaving behind a mineralized replica of the original ammonite structure.