I can't see your pic but p134 of Field is wrong in 1987 - Warwick Sun Brooch - and changed in 1997 - Surrey Brooch - and finally the QD calls it Queen Mary's Richmond brooch.
Queen Mary wore it suspended from the pearl necklaces for the Devonshire House Ball.
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--Previous Message-- : On page 134 of Field, the "Warwick Sun : Brooch" is shown in a drawing. The : brooch was a wedding present from the family : of the Earl of Warwick to Princess Victoria : Mary. A photograph from the 1897 Devonshire : Ball is provided to show that Queen Mary : wore it. A photograph of Queen Elizabeth II : at the opening of the New South Wales : Parliament in 1953 is provided and : referenced as the only time she wore it to : date. Both photos are small and the brooch : is indistinct. I have found other views of : this event. : : Drawing from Field : : : : :