What an interesting thread this is!

The "copy" was photographed on Princess Christopher of Greece, but how and when she acquired this set is unknown to me.





Re the Russian items.

This 2012 paper on the Faberge research site indicates that the whereabouts of the tiara and brooch are unknown.

https://fabergeresearch.com/newsletter-2012-spring-2/


That has made me wonder if the Greek tiara was in fact the original (modified by removing the base) which was purchased by the Count of Paris for his daughter, Francoise, when she married.

An easy to follow site on Fersman's catalogue is at https://www.romanovempire.org/topics/academician+fersman

For the turquoise set see https://www.romanovempire.org/media/illustrations-of-the-catalog-the-diamond-fund-of-the-ussr-p-81-737956

Queen Sophie of Greece was given an elaborate and expensive set of turquoises when she married, but others have always argued that they are not the jewels worn by Princess Christopher. That parure is a great mystery as, although it was reported in the press and the Empress Frederick commented on it in letters, no photos of it have surfaced.