Not a surprise, of course, but King Charles III wore the expected "uniform" for the State Opening of Parliament: ermine-trimmed robes, Imperial State Crown, and Garter collar with a gem-encrusted Saint George's figure (is it the "greater George"?).





Queen Camilla wore King George IV's Diamond Diadem, a diamond riviere and the earrings of her personal diamond demi-parure:







Now, the inevitable (and probably unsolvable) question: which diamond riviere is it? Among the possible options:
- Queen Victoria's Coronation riviere (without the Lahore diamond drop)
- Queen Alexandra's diamond riviere (wedding gift from the City of London)
- Queen Mary's Teck diamond riviere
- Queen Elizabeth's Coronation riviere.

It is difficult to make a definitive assertion, but I would exclude the Teck riviere (whose diamonds are a bit smaller the the ones of the other rivieres) and Queen Elizabeth's Coronation riviere (the setting of the diamonds, as visible in Hugh Roberts' The Queen's Diamonds, looks quite different). Then, judging from the length of the necklace and the shape of the front diamonds, I would guess it is Queen Alexandra's riviere - but without certainty.