Some prices for diamonds (3)
I believe the answer is:
ice
'diamonds' is the definition.
(slang term for diamonds)
'some prices for' is the wordplay.
'some' indicates a hidden word (some of the parts of the word are used).
'ICE' is hidden in the letters of 'prices for'.
(Other definitions for ice that I've seen before include "Block" , "A state of water" , "Solid water" , "such an age" , "Do cake decoration" .)