You're probably right, and perhaps that's why I like it. I have seen it called a fringe tiara/necklace, but certainly it's more ornamented than the others. In the closeup (and thanks for the lovely photo), it reminds me of the Surrey tiara that we'd so much like to see again.
I hope Madeleine does receive this tiara, since it's so nice on her. I'm really not crazy about that bar of diamonds at the base, however. Converting necklace to tiara should be possible without making the base awkward.