Diamonds appropriate for waterproof container? (3,3)
I believe the answer is:
ice bag
'waterproof container?' is the definition.
(I've seen this before)
'diamonds appropriate' is the wordplay.
'diamonds' becomes 'ice' (slang term for diamonds).
'appropriate' becomes 'bag' (I've seen this in other clues).
'ice'+'bag'='ICE-BAG'
'for' is the link.
(Other definitions for ice bag that I've seen before include "Waterproof container" , "Cold item applied to reduce swelling" , "cold compress" , "cooler" , "Chilled sack applied to swellings, etc" .)