There are tiaras, and then there are tiaras like the Londonderry Diamond Tiara. This piece dates to the middle of the nineteenth century; it was a part of a diamond parure made for the family in 1854 by Garrard, although the tiara itself was not originally an all-diamond piece. The center of each element was originally designed to hold a pearl, and the tiara could also be worn topped by tall pear-shaped pearls, increasing the height of the piece substantially.
Today, the diamonds at the center of each element are mounted en tremblant. The piece is almost a complete circlet, encircling nearly the entire head of the wearer. (The tiara is magnificent, but it’s not the only one the Londonderrys own — they’ve also got a famous set of amethysts, given to them by Alexander I of Russia, and a pearl necklace that can be worn as a tiara.)
In 1897, Theresa, the wife of the 6th Marquess of Londonderry, wore the tiara as a part of her costume at the famous Devonshire House Ball. Theresa went to the ball as Empress Maria Theresa of Austria, and for the occasion, she had the diamond tiara transformed into a full-on imperial crown, using necklaces and bracelets to mimic the arches and cross from Maria Theresa’s original crown — you can see the effect here.
Theresa’s daughter-in-law, Edith, began wearing the diamond tiara after her husband inherited the Londonderry title in 1915. She wore it to the coronation of King George VI and Queen Elizabeth in 1937. Even better: the Londonderrys still own this tiara, though they’ve kindly shared the piece with all of the rest of us. Along with their amethysts, the tiara is on display in the jewelry room at the Victoria & Albert Museum in London (AKA Mecca for magpies). I saw it there in 2013, and it is breathtaking. Hope some of the rest of you get to make a similar pilgrimage!