Thanks for those picture of the garnet parure Arthur.
The brooch is one of those pieces that - while not quite a mystery - was unique it that it seems to be a one-time wearing by HM (that we know of).
I think that the parure, being of coloured stones, does not fit in with HM's usual jewellery choices.
This has made me think - can anyone recall anytime that HM has worn any coloured jewellery, that is, necklace or even earrings for that matter, as part of her daytime wardrobe (brooches not withstanding)?