Imitation gem made from nine others (10)
I believe the answer is:
rhinestone
'imitation gem' is the definition.
(I've seen this before)
'from nine others' is the wordplay.
'from' indicates anagramming the letters (from the letters).
'nine'+'others'='nineothers'
'nineothers' with letters rearranged gives 'RHINESTONE'.
'made' is the link.
(Other definitions for rhinestone that I've seen before include "Phoney" , "Rock" , "one not really brilliant?" , "cheap jewellery" , "Imitation diamond" .)