Cullinan Diamond
The Cullinan diamond was found below the surface at Premier Mine in Cullinan, Transvaal Colony, by Frederick Wells, surface manager at the mine, on 26 January 1905. It was approximately long, wide, deep, and weighed . Newspapers called it the "Cullinan Diamond", a reference to Sir Thomas Cullinan, who opened the mine in 1902. It was three times the size of the Excelsior Diamond, found in 1893 at Jagersfontein Mine, weighing . Four of its eight surfaces were smooth, indicating that it once had been part of a much larger stone broken up by natural forces. It had a blue-white hue and contained a small pocket of air, which at certain angles produced a rainbow, or Newton's rings.
Crown Jewels of the United Kingdom
The regalia contain 23,578 stones, among them Cullinan I, the largest clear cut diamond in the world at , set in the Sovereign's Sceptre with Cross. It was cut from the largest gem-quality rough diamond ever found, the Cullinan Diamond, discovered in South Africa in 1905 and presented to Edward VII. On the Imperial State Crown are Cullinan II (second-largest of the Cullinan diamonds), the Stuart Sapphire, St Edward's Sapphire, and the Black Prince's Ruby – a large spinel given to Edward the Black Prince by a Spanish king in 1367. The Koh-i-Noor diamond, originally from India, has featured on three consort crowns. A small number of historical objects at the Tower are either empty or set with glass and crystals.