1° perhaps it's Nelly (Field spécialist) who wrote :
FLORAL SPRAY BROOCH
This brooch is a floral spray looped around an enormous pearl. Queen Elizabeth II's "Diamond and Pearl Spray Brooch" or "Lyre Brooch." On page 112 Field says that it is "a floral spray looped around an enormous pearl."
She wore it to New Zealand in 1974 also to Jordan.