Dawn's quality captures gold (6)
I believe the answer is:
aurora
'dawn's' is the definition.
(synonyms)
'quality captures gold' is the wordplay.
'quality' becomes 'aura' (aura is a kind of quality).
'captures' indicates putting letters inside.
'gold' becomes 'or' ('or' is the heraldic name for gold).
'aura' enclosing 'or' is 'AURORA'.
(Other definitions for aurora that I've seen before include "Atmospheric luminance" , "Roman goddess of the dawn" , "dawn arrives" , "Roman goodess of the dawn" , "Orange" .)