Beauty queen's crown (5)
I believe the answer is:
tiara
'beauty queen's crown' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for tiara that I've seen before include "Jewelled head wear" , "Ornamental head gear" , "Jewelled head-ornament" , "Small crown" , "Jewelled head band" .)