Why is this ammonite iridescent?
I bought this iridescent ammonite and it came with a description card but it didn't say why it was iridescent. Is it because it still contains traces of the original shell?
Here is the latest info on ammonoid iridescence.
excerpts and figure from:
Klug, C., Korn, D., De Baets, K., Kruta, I., & Mapes, R.H. (eds.) 2015
Ammonoid Paleobiology: From Anatomy to Ecology.
Springer Publishing, Topics in Geobiology, 43:1-934
Background
In the last decade, hundreds of ammonite specimens with undescribed iridescent color patterns have been discovered. Keupp (2005) was the first to describe and illustrate this occurrence, although Reyment (195
