Say gold piece (7)
I believe the answer is:
element
I believe this is a double definition.
'say gold' is the first definition.
(I know that Au is a type of element)
'piece' is the second definition.
(I've seen this before)
(Other definitions for element that I've seen before include "Iron, for instance - part of an electric kettle" , "Chemical building block" , "He, say" , "Wire in electric fire" , "Constituent of universe" .)