Gold and black sphere (3)
I believe the answer is:
orb
'sphere' is the definition.
(orb is a kind of sphere)
'gold and black' is the wordplay.
'gold' becomes 'or' ('or' is the heraldic name for gold).
'and' is a charade indicator (letters next to each other).
'black' becomes 'b' (as in pencil classifications).
'or'+'b'='ORB'
(Other definitions for orb that I've seen before include "Ring" , "Part of royal regalia" , "Jewelled ornament" , "Sphere for a sovereign" , "Sphere - eye" .)