There's nothing like a wedding to provoke a cascade of royal diamonds. On her big day, Kate wore the Cartier Halo tiara, which is made up of 16 graduated scrolls set with 739 brilliant diamonds and 149 baton diamonds and was bought by King George VI for the queen mother. It was gifted to the queen on her 18th birthday, and her sister Margaret borrowed it for the coronation. It has also been worn by Princess Anne.