What wonderful information Ursula. That clarifies this and certainly takes the sapphire tiara out of the running. I was dubious about all the photos floating around on the internet saying these were engagement gifts which is why I was trying to find some more firm information on the subject. I knew there had to be something written on this somewhere. So much good information only in Russian alas.

Massie = Robert K. Massie who wrote the famous biography of Nicholas and Alexandra. He's usually reasonably reliable.