Part of a tooth (6)
I believe the answer is:
enamel
'part of a tooth' is the definition.
(I know this)
This is all the clue.
(Other definitions for enamel that I've seen before include "Ale men (anag.)" , "found on crowns" , "Vitrified coating for metal etc" , "Hard gloss paint" , "Shiny layer on surface" .)