Gold pieces forming circles (6)
I believe the answer is:
orbits
'circles' is the definition.
(I know this)
'gold pieces' is the wordplay.
'gold' becomes 'or' ('or' is the heraldic name for gold).
'pieces' becomes 'bits' (bit is a kind of piece).
'or'+'bits'='ORBITS'
'forming' acts as a link.
(Other definitions for orbits that I've seen before include "Whole rounds" , "Paths of e.g. planets" , "Goes around like paths of planets" , "Bistro (anag)" , "Planetary paths" .)