Steep rocks traversed by snoop (6)
I believe the answer is:
pricey
'steep' is the definition.
(I've seen this in another clue)
'rocks traversed by snoop' is the wordplay.
'rocks' becomes 'ice' (both can informally mean diamonds).
'traversed by' means one lot of letters goes inside another (some letters cross or traverse others).
'snoop' becomes 'pry' (I've seen this in another clue).
'ice' put into 'pry' is 'PRICEY'.
(Other definitions for pricey that I've seen before include "Costly" , "Expensive" .)