The Queen chose aquamarines for the Spanish State Banquet yesterday; here’s more about the jewels’ history.
The aquamarines came from Brazil; in 1953, The President and Brazilian people gave Her Majesty a gift for her coronation, in the form of an aquamarine and diamond necklace with matching earrings.
Blue stones were sought over a year to perfectly match; The Queen had a tiara made by Garrard in 1957 to go with the necklace and earrings. She received a bracelet and brooch, made to match the first Brazilian gift, in 1958.
The stones are all large rectangular aquamarines, set in scrolls of diamonds and platinum. The tiara is a bandeau style piece, with three upright aquamarines with diamond scalloped surrounds. Order of Splendour says that the uprights are detachable, as is the pendant of the necklace.
Read about the brooch.