This fossil was displayed on August 2022, at the Harvard Museum of Natural History
in Cambridge,Massachusetts, USA. It is an ammonite fossil is called Placenticeras (Meek, 1870). The creature lived during the Upper Cretaceous Period
(80 million years ago). Fossil was found in Bearpaw Formation on the Blackfeet Reservation of southern Alberta, Canada. Specimen on loan to museum from the Mineral Trust.
The amazing iridescent colors are the mineral ammolite (aragonite).