I was too hasty. It could be the Koh-i-noor - without its setting of rose diamonds - from which Cullinan I is suspended, with Cullinan II pinned above them, as Barbara suggested.
We need to determine the year, which looks to me like their first Parliament as Alexandra is in mourning.
EDIT: not their first Parliament. --Previous Message-- : : They are Cullinan I and II - the mega : version of the Cullinan brooch of III and : IV. : : I and II had been given to the King and he : bought VI for Alexandra. : : I and II are now set in the regalia. : : I'll see what else I can find about her : jewels. : : : : : --Previous Message-- : : : --Previous Message-- : I recently obtained the cabinet card below. : I : think it is the state opening of Parliament : around c1904-05 based on the fact Alexandra : is wearing her collier resille made for her : in 1904 by Cartier and later modified for : Queen Mary. : : However, its the large brooch that Alexandra : is wearing on her breast that has me : puzzled. it looks very similar to the : cullinan "granny's chips" but that : wasn't created till 1911. Does anyone have : any ideas? : : : : The top-part might be the Koh-i-Noor diamond : in its brooch-setting. But up to now no idea : about the pear-shaped pendant . : : Royal Collection says, that picture is from : State Opening of Parliament 1902 - an error : from RC or was the Collier Résille made : earlier? More : : Edit: link to Royal Collection added: : : http://www.royalcollection.org.uk/collection/2106303/formal-portrait-of-queen-alexandra-1843-1925 : : :