Fruit containing popular mineral (7)
I believe the answer is:
olivine
'mineral' is the definition.
(thesaurus)
'fruit containing popular' is the wordplay.
I cannot really understand how this works, but
'popular' could be 'in' and 'in' is found within the answer.
'fruit' could be 'olive' (I've seen this before) and 'olive' is present in the leftover letters.
This accounts for all the letters.
This explanation may well be incorrect...
(Other definitions for olivine that I've seen before include "Clear green gemstone" , "Dark green mineral" , "stone" , "mineral in rock" .)