Name: Cleoniceras besaiei Ammonite
Time Period: Upper Early Cretaceous, Albian Stage
Locality: Mahajanga Province, Madagascar
This ammonite species is known as Cleoniceras, and the preservation is such that most of the original iridescent shell is preserved. The iridescence is a result of light passing through the layers of aragonite and conchiolin grown by the ammonite in life.
The iridescence changes depending on the angle viewed by the observer and the type of light illuminating the shell.