I think it's the amethyst tiara but light must be reflecting on the central stone.
--Previous Message-- : I wonder if this photo shows Queen Mary's : amethyst tiara in an earlier setting than : the one we are familiar with? : : The setting on the sides appears to be the : same but the centre is different. Or could : this be an entirely different tiara? : : If Queen Mary is wearing the Love Trophy : collar, then this photo has to have been : taken after March 1901 - the date Roberts (p : 154) gives for the creation of that jewel. : : Yet, we have photographic evidence of the : tiara having looked the same from 1893 to : modern times. : : : : Tiara setting as we know it. : : Source: Illustrated London News 4 May : 1935. It says the photo was taken in 1893. : : : : : : : Modern photo : : : :