Crack stone in date (5)
I believe the answer is:
tryst
'date' is the definition.
(I've seen this before)
'crack stone' is the wordplay.
'crack' becomes 'try' (I've seen this in other clues).
'stone' becomes 'st'.
'try'+'st'='TRYST'
'in' acts as a link.
(Other definitions for tryst that I've seen before include "Pre-arranged (secret) meeting" , "Lump (of gold, etc)" , "Date" , "Lovers' appointment" , "An archaic lovers' meeting" .)