Lovely! Like yesterday's ruby brooch, Prince Albert's Brooch has a very simple design, but it is such a timeless elegance!
It is quite surprising that Queen Elizabeth II has never, or almost never, worn this brooch along with her sapphire suite of jewellery, presented by her father as a wedding gift in 1947. I think they would make a very nice match, as they are from the same period of time (mid-19th century) and style.
The Countess of Wessex was present, and wore the Queen Mother's diamond clips:
Princess Alexandra of Kent wore her pearl choker with a diamond lozenge-shaped clasp, and her six-petal diamond brooch:
Princess Michael of Kent wore a necklace of cabochon smoky stones (aquamarines?) in gold setting, with matching earrings: