At the front of the crown band is the large cushion-shaped brilliant, Cullinan II, the second largest stone cut from the Cullianan Diamond (also known as the Second Star of Africa). At the back of the band is the large oval sapphire known as the 'Stuart Sapphire'. The two large stones are linked by an openwork frieze, containing eight step-cut emeralds and eight sapphires, between two rows of pearls.
Above the band are two arches (or four half-arches), each springing from a cross-pattée. The front cross is mounted with a large, irregular cabochon red spinel, known as the 'Black Prince's Ruby'. In its history the stone was pierced for use as a pendant, and the upper hole later plugged with a small cabochon ruby in a gold slip mount. The remaining three crosses are each mounted with a step-cut emerald mounted as a lozenge. The crosses alternate with four fleurs-de-lis, each with a mixed-cut ruby in the centre. Both crosses and fleurs-de-lis are further mounted with diamonds. The crosses and fleurs-de-lis are linked by swags of diamonds, supported on sapphires.
The arches are cast as oak leaves, set with diamonds, each having paired pearl acorns in diamond cups projecting from the sides. At the intersection of the arches are suspended four large pear-shaped pearls in rose-diamond caps, known as 'Queen Elizabeth's Earrings'. The arches are surmounted by a monde of fretted silver, pavé-set with brilliants, with a cross-pattée above, set in the centre with an octagonal rose-cut sapphire known as 'St Edward's Sapphire'.
The Crown is fitted with a purple velvet cap and ermine band. Small plates on the reverse of the 'Black Prince's Ruby' and the 'Stuart Sapphire' are engraved to commemorate the history of the Crown.
The Imperial State Crown, or Crown of State, is the crown the monarch exchanges for St Edward's Crown, at the end of the coronation ceremony. Before the Civil War the ancient coronation crown was always kept at Westminster Abbey and the monarch needed another crown to wear when leaving the Abbey. The Imperial State Crown is also used on formal occasions, such as the annual State Opening of Parliament. The term imperial state crown dates back to the fifteenth century when English monarchs chose a crown design closed by arches, to demonstrate that England was not subject to any other earthly power.
This crown was made for the coronation of King George VI in 1937 but is closely based on a crown designed for Queen Victoria in 1838 by the crown jewellers of the time, Rundell, Bridge & Rundell.