Diamonds? Spotty types have no need of them! (3)
I believe the answer is:
ice
'diamonds?' is the definition.
(slang term for diamonds)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for ice that I've seen before include "Finish decorating the Christmas cake" , "Frozen liquid" , "Glaciate" , "Diamonds (slang)" , "Chill - harden" .)