PJ I am not 100% sure, but this may just be a hat ornament, used to attach the feathers, as opposed to a brooch. Here is another example.
Cheers! Bryce
--Previous Message-- : : I found this photo on the site listed under : Queen Mary's photo. It's the circled brooch : I'm interested in on her hat. Queen Mary : photo : You'll need to go just over half way down : the site to Empress Marie Feodorovna's : Sapphire Brooch. It's the third photo under : this heading. Any help will be appreciated. : PJ : :