While looking for pictures of the 1937 Coronation (to try to identify the pearl necklace worn by Queen Elizabeth), I found this picture of Queen Mary wearing two brooches:
I think that the large central brooch worn by Queen Mary in the middle of her corsage could be the unidentified diamond "clips" we had spotted a few months ago on a video:
I do not identify the large square brooch worn by the Queen on her collar. Does anyone know which brooch it is, of which stones iti is made, and its current whereabouts?