Diamond found in farmland (7)
I believe the answer is:
infield
'diamond' is the definition.
(I know that diamond can be written as infield)
'in farmland' is the wordplay.
'farmland' becomes 'field' (I can't explain this - if you can you should believe this answer much more).
'in'+'field'='INFIELD'
'found' acts as a link.
Can you help me to learn more?
(Other definitions for infield that I've seen before include "From part of playing area" , "down from fence?" , "Area inside racetrack" , "close to batsman?" .)