Butterfly buff's catalogue record set by exotic peridot (13)
I believe the answer is:
lepidopterist
'butterfly buff's catalogue record set by exotic' is the definition.
I can't tell whether this definition defines the answer.
'peridot' is the wordplay.
I cannot quite see how this works, but
an anagram of 'peridot' is 'idopter' which is located in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for lepidopterist that I've seen before include "one with commas to check?" , "Butterfly expert" , "One who studies butterflies and moths" , "Student of moths and butterflies" , "Butterfly enthusiast" .)