Shiny as a metal (7)
I believe the answer is:
silvery
I believe this clue is a double definition.
'shiny' is the first definition.
'as a metal' is the second definition.
(Other definitions for silvery that I've seen before include "Epithet for the moon" , "Having a clear ringing tone; like a precious metal" , "Whitish; gently ringing" , "Like one precious metal" , "like a mirror?" .)