Posted by Baxter on October 1, 2015, 9:47 am, in reply to "Ah! The banner"
The photo of Lady Louise was taken at the 2011 Royal Caledonian Ball and is from the website of photographer Dafydd Jones which I recall Cynthia pointing out at the time.
I'm not familiar with the Argyll jewels but as I was making this banner I kept thinking there was something familiar about the tiara. Then I realized it has the same design as the necklace/tiara worn by Mary, Duchess of Devonshire.
We have always assumed these were sapphires even though I've never seen a good-quality color image, but I don't think they are opals. In some of the photos the stones appear too dark to be opals and of course it was common for designs to be repeated.