Fruit with large stone (5)
I believe the answer is:
pearl
'stone' is the definition.
(I have seen 'precious stone' mean 'pearl' so perhaps 'stone' could also mean 'pearl')
'fruit with large' is the wordplay.
'fruit' becomes 'pear' (pear is a kind of fruit).
'with' says to put letters next to each other.
'large' becomes 'L' (eg in clothes sizes).
'pear'+'l'='PEARL'
(Other definitions for pearl that I've seen before include "Lustrous structure inside an oyster-shell" , "Gem from the sea" , "Gem from oyster" , "Oyster's gem" , "Smooth lustrous round structure of calcium carbonate" .)