My favorite royal ever is Queen Alexandra of Great Britain and Ireland. She was the most elegant, beautiful woman, and could wear yards of pearls and diamonds without looking vulgar and bourgeois. She aged ridiculously well, and even at her coronation, when she was in her fifties, she looked as beautiful as ever. This tiara is inspired by a circlet of hers that she wore with and without a sort of celtic knotwork design that would be attached between each fleur-de-lys ornament. I of course added my own personal touch, and put oriental pearl spikes surmounting each fleur-de-lys, and and "pearl and diamond" cluster between each element.
Queen Alexandra in her original tiara, wearing the huge rows of diamonds and pearls she used to cover a scar on her neck.