The Crown is of a design similar to St Edward's Crown: it includes a base of four crosses pattee alternating with four fleurs-de-lis, above which are four half-arches surmounted by a cross. Inside is a velvet cap with an ermine border. The Imperial State Crown includes several precious gems, including: 2,868 diamonds, 273 pearls, 17 sapphires, 11 emeralds, and 5 rubies. It includes several famous jewels. The Cross atop the Crown is set with a sapphire taken from the ring of Edward the Confessor. The Black Prince's Ruby is set on the front cross pattee. Furthermore, the famous Cullinan II, or Lesser Star of Africa, is set on the front of the Crown.
It is generally worn at the end of a coronation when the new monarch departs from Westminster Abbey, though it was actually worn during the ceremony by Queen Victoria and King Edward VII, both of whom complained about the weight of the normally used crown, St Edward's Crown. Furthermore, it is worn annually by the Queen at the State Opening of Parliament. Traditionally, the Crown and other jewels leave in their own carriage and arrive at the Palace of Westminster prior to the Queen's departure from Buckingham Palace. They are then transported to the Robing Room, where the Queen dons her robes and wears the Crown.
The Imperial State Crown, except when in use at State Openings, and the other Crown Jewels, may be found on display at Jewel House in the Tower of London.