Capital jewellery (5)
I believe the answer is:
tiara
This clue might be a double definition.
'capital' is the first definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'jewellery' is the second definition.
(tiara is a type of jewellery)
Can you help me to learn more?
(Other definitions for tiara that I've seen before include "special headgear" , "Woman's head ornament" , "Item of jewellery" , "Half a crown!" , "Great delight" .)