Help identify , very old. Turquoise diamond brooch with tube screw hinge

[Toekneetang]

This looks incredibly old and I'm wanting to sell it but want an honest evaluation of it
Here is a link to my drop box with all the photos of every angle . It comes apart by pulling out a long screw which allows the turquoise stone to drop out from the middle creating three seperate pieces
https://www.dropbox.com/sh/lizqj0ekiaxzf3f/AACSCz3o2MFs9tQEVn5vAKuMa?dl=0
From my research I think it's Persian turquoise with old mine cut diamonds
I have found a brooch similar to this that went for $16,000