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.
Petra Diamonds
The mine, previously known as Premier Diamond mine, is renowned for producing many of the world's largest and most famous diamonds, including the Cullinan Diamond, the world's largest gem diamond, at rough. Sir Thomas Cullinan, the former chairman of the Premier Diamond Mine, presented the Cullinan to England's King Edward VII in 1905. The Great Star of Africa, which sits in the Sceptre of the Crown Jewels, was produced from the Cullinan Diamond, and was until recently acknowledged to be the largest cut diamond in the world, weighing in at . In 1985 it lost the record to the Golden Jubilee, which was found in the same mine as the Cullinan and weighed in its polished state. More than a quarter of all diamonds weighing more than have originated from Cullinan. It is also the world's only significant source of blue diamonds. One of these famous large blue diamonds was cut into several stones and made into a necklace which subsequently became known as the Cullinan Blue Diamond necklace.