Lady Londonderry famously dropped this tiara down the loo at Westminster Abbey during the coronation of Edward VII in 1902. She spent most of the ceremony trying to retrieve it. Set with spectacular Siberian amethysts, the Londonderry Tiara was given by Tsar Alexander I to an earlier Lady Londonderry, in 1821.
Boucheron Harcourt Tiara. Gold, silver and diamond tiara, the base and top outlined by channel-set diamonds enclosing a continuous line of ribbons, the space between filled with seven emeralds with rectangular cut corners within open oval frames graduated in size towards the back. These are surmounted by groups of collet-set diamonds and supported below by leafy sprays linking the emeralds The emeralds have been replaced. Boucheron, Paris 1900-1913. Go to source for further info.
A belle epoque tiara, 1908, by Chaumet. Made for the Marquis de Talhouet, a classic scrolling foliate tiara, with large circular diamonds at the centre of each scroll and topped by a larger, cushion-cut diamond.