Sadly for us the State visit to the UK was at a time when the press was still reasonably deferential and rarely took unauthorised snaps of the visiting royals.
I have just looked at what I have collected on the State visit by the Emperor and Empress in 1891. What ever tiara the Empress wore, it was said to have large stones. The cuttings I have show that, for the gala Opera evening, Queen Alexandra wore the Ladies tiara. I should do more of a hunt in the media as no doubt there will be a sketch of the evening.