We don't know exactly what pieces are part of the family trust that holds jewels and what is still private.
We also have no clue what the family collection and individual members of the family have when it comes to jewels.
However Emma's fringe tiara in this version is most likely completely part of the collection. The sapphire set is part of the collection and the lower part is probably part of it too.
I would not be surprised if Beatrix still owns her first tiara and if several ladies have private jewels and potentially even tiara's as part of their private collection.

Previous Message
Absolutely not! None of the tiaras in the Dutch collection are owned privately. There are no former rules but the largest tiaras are reserved for the (reigning) Queen although exceptions are sometimes made for the heir or wife of the heir. Minor royals usually wear smaller pieces.

Previous Message
Was it given to Mabel to wear exclusively?

Previous Message
Actually it's not Mabel's tiara but Queen Emma's fringe tiara. The original version had chocolate diamonds on top and now the diamonds of Emma's sapphire tiara are used.
I'd love to see the chocolate diamonds used on it at least once and it would be nice if they added new diamonds so this tiara and the sapphire tiara can be worn at the same time.

Previous Message
Perhaps an idea for Queen Mathilde to create a lookalike tiara.
Use the 11 diamond from the provinces tiara on a frame