Gold particle hunter (5)
I believe the answer is:
orion
'hunter' is the definition.
(I've seen this before)
'gold particle' is the wordplay.
'gold' becomes 'or' ('or' is the heraldic name for gold).
'particle' becomes 'ion' (I've seen this before).
'or'+'ion'='ORION'
(Other definitions for orion that I've seen before include "Constellation - mythological hunter" , "Large constellation" , "Mythical Greek hunter turned into constellation" , "Greek hunter of myth or bright constellation" , "Constellation that includes Betelgeuse" .)