Funny mineral found in mountain pass (7)
I believe the answer is:
comical
'funny' is the definition.
(I know that funny can be written as comical)
'mineral found in mountain pass' is the wordplay.
'mineral' becomes 'mica' (mica is a kind of mineral).
'found in' indicates putting letters inside.
'mountain pass' becomes 'col' (col is a kind of mountain pass).
'mica' going within 'col' is 'COMICAL'.
(Other definitions for comical that I've seen before include "Rich" , "Witty" , "priceless" , "'Amusing, funny (7)'" , "Amusing or droll" .)