Below is what was identified as the Russian sapphire on RJWMB:
However there doesn't seem to be (I believe) much proof that it is actually Russian. It's assumed QM bought it from the estate of Marie Feodorovna but she could have bought it from a number of other sources, other emigre's, Habsburg's, Hohenzollern's etc or been gifted or bought it from endless sources. I'm pretty sure QM was source agnostic.
This is the brooch that QEQM gave Diana as a wedding present:
However this brooch is also very much source unknown. Perhaps a Greville piece, a gift, the UK not only liberated lot of countries but gave homes and to leave countries on the brink of occupation and assistance in a number of forms to other royals. Maybe also purchased after the war from another ship-wrecked family?
What's everyone else's thoughts or knowledge on these two pieces?