Gold mace perhaps an omen (7)

I believe the answer is:

auspice

'an omen' is the definition.
(auspice is a kind of omen)

'gold mace perhaps' is the wordplay.
'gold' becomes 'au' (Au is the chemical symbol for gold).
'mace perhaps' becomes 'spice' (mace is a kind of spice).
'au'+'spice'='AUSPICE'

(Other definitions for auspice that I've seen before include "sponsorship" , "Omen - I use cap (anag)" , "Omen; epic USA (anag.)" , "future promise" , "Omen (archaic)" .)

I've seen this clue in The Telegraph.

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