Returned gold below - more rich in tone (7)
I believe the answer is:
rounder
'rich in tone' is the definition.
The definition and answer are not the same part of speech.
'returned gold below more' is the wordplay.
'returned' shows that the letters should be reversed in order.
'gold' becomes 'or' ('or' is the heraldic name for gold).
'below' becomes 'under' (synonyms).
'more' says to put letters next to each other (some letters added to the previous ones).
'or' back-to-front is 'ro'.
'ro'+'under'='ROUNDER'
Can you help me to learn more?
(Other definitions for rounder that I've seen before include "More rotund" , "Score at baseball-type game" , "Score in bat and ball game" , "More spherical" , "Or under (anag.)" .)