Glossy finish (6)
I believe the answer is:
enamel
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">glossy finish</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for enamel that I've seen before include "hard cover" , "hard stuff" , "Outer tooth material" , "found on crowns" , "Hard shiny coating on surface" .)