I've succeeded getting iridescent with this Cycles node setup:
Physical iridescence in Cycles?
This did the job, however I need a transparent/clear iridescence like this
So I tried plugging the final output into a mix shader between Glass BDSF and transparent. However this still produces a black, barely iridescent material.
How can I get the results below from what I have? I don't want to use code but rather stay with nodes