Drink and diamonds affected date (4,3)
I believe the answer is:
iced tea
'drink' is the definition.
(iced tea is a kind of drink)
'diamonds affected date' is the wordplay.
'diamonds' becomes 'ice' (slang term for diamonds).
'affected' is an anagram indicator.
'date' is an anagram of 'dtea'.
'ice'+'dtea'='ICED TEA'
'and' is the link.
(Other definitions for iced tea that I've seen before include "Cold summer drink" , "Chilled drink" , "Cool drink" .)