Imitation gem (10)
I believe the answer is:
rhinestone
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">imitation gem</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for rhinestone that I've seen before include "imitation gem" , "Rock" , "Fake gem" , "it's made of paste" , "Phoney" .)