If you’re intrigued by the origin of gemstones, then you’re probably going to love ammolite. Ammolite is iridescent fossilized ammonite shells found in Southern Alberta, Canada.http://4csblog.gia.edu/2014/ammolite-fashionable-fossil

for more information refer below:
http://4csblog.gia.edu/2014/ammolite-fashionable-fossil(extracted from GIA)