It is the only crown for a British king or queen to be made of platinum.

[1] The crown is decorated with about 2,800 diamonds, most notably the 105-carat (21.0 g) Koh-i-Noor in the middle of the front cross, which was acquired by the East India Company after the Anglo-Sikh Wars and presented to Queen Victoria in 1851,[2] and a 17-carat (3.4 g) Turkish diamond given to her in 1856 by Abdulmejid I, sultan of the Ottoman Empire, as a gesture of thanks for British support in the Crimean War.

Most of the other diamonds originated from Queen Victoria's Regal Circlet.

[4] After the death of the King, Queen Elizabeth, known thereafter as the Queen Mother, did not wear the full crown, but wore it minus the arches as a circlet at the coronation of her daughter, Elizabeth II, in 1953.

[5] In its full form, it was placed on top of the Queen Mother's coffin for her lying-in-state and funeral in 2002.