Most of what makes one green metal ring (7)
I believe the answer is:
environ
'ring' is the definition.
(I know that ring can be written as environ)
'most of what makes one green metal' is the wordplay.
I cannot really understand how this works, but
'of' could be 'o' and 'o' is present in the answer.
'one' could be 'i' (Roman numeral) and 'i' is found within the answer.
'metal' could be 'v' (V is an example) and 'v' is found within the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Another definition for environ that I've seen is " Ring".)