Tiffany Pearls that brought tears!

by Liz
(France)

Where can I sell a Tiffany opera length pearl necklace, bought in Tiffany New York in 1967 and now without certificate of authenticity.

Because I can't prove its provenance now, although I have a photo of myself wearing it, I think I need to find an appraiser with "X-ray" equipment in order to establish its value?

Retail prices have a mark-up. I don't know how high this is, so these prices don't help me to find a fair asking price. There are 93 x 8-9mm cream pearls of exactly the same size.
I have photos but I always need my son, or grandson! to upload things for me.