Kept at the Tower of London since the 17C, the Crown Jewels have since 1971 been displayed in the imposing 19C Waterloo Barracks. Most of the pieces are used in the coronation ceremony. The earliest date from Charles II's coronation at the time of the Restoration (1660). Of inestimable value, the precious stones include the world's largest diamond, the great Star of Africa (530 carats). The Imperial State Crown incorporates 3 733 stones.