Diminutive one clutches stone (3)
I believe the answer is:
nut
'stone' is the definition.
(thesaurus)
'diminutive one clutches' is the wordplay.
'one clutches' says the answer is hidden in the clue (I've seen 'clutching' mean this).
'NUT' can be found hidden inside 'diminutive'.
(Other definitions for nut that I've seen before include "Hard kernel of minutiae" , "Crank" , "Bonce" , "Screwing block" , "Fanatic (slang)" .)