Is pyrite responsible for the gold coloration of the ammonites in the Posidonia Shale? No, it isn´t!

[rocket]

It is generally assumed that the gold-colored ammonites in Posidonia slate got their color from pyrite intercalation. This has now been comprehensively investigated for the first time and it has been established that this is not the case. Phosphates are responsible for the gold coloration, the pyrite that is sometimes also found probably came later through cracks or decay.
I add the article as open PDF,  comes from Earth-Science Reviews, Volume 238, March 2023, 104323

 

1-s2.0-S0012825223000120-am.pdf

 

Edited November 9 by rocket

[pachy-pleuro-whatnot-odon]

That's indeed a surprising finding! Informative. Thanks for sharing!