I was actually just going to comment when I saw this new info that it certainly does look like high end costume jewelry to me. I deal with and have handled a lot of fine antique jewelry and you can most certainly tell a crystal from a real Diamond if you look at them long enough [emoji4]
You can also tell from the clasp in the back and also the luster of the stones. They have the shine of a crystal.
Plus there’s also some deductions we could do such as: we’ve never seen this piece before and if it were from the Royal collection it would’ve mostly likely be worn before on one of the more senior Royal ladies. They hardly ever loan out a necklace of this magnitude (assuming it was real) to minor royals on the first go around. There is still a Precedence with Royal jewelry.
Also if it were a private gift to Sofia I’m sure she would’ve worn this before either to show respect to the giver or because it would’ve gone good with her new pearl toppers on her Tiara. Plus I’m not entirely sure but this doesn’t look like a gift CArl Philip would gift her. The real version of this would be very costly and they don’t seem like the type of couple to give each other lavish gifts.
Just my two cents.
In other words: the original version of the tiara was awful. 
