Instrument made of wood set in stone (6)
I believe the answer is:
spinet
'instrument' is the definition.
(spinet is a kind of instrument)
'wood set in stone' is the wordplay.
'wood' becomes 'pine' (pine is a kind of wood**).
'set in' is an insertion indicator.
'stone' becomes 'st'.
'pine' inserted inside 'st' is 'SPINET'.
'made of' acts as a link.
(Other definitions for spinet that I've seen before include "A small harpsichord of old" , "Instep (anag)" , "Step in with old musical instrument" , "Old keyboard instrument" , "Harpsichord-like keyboard instrument" .)