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.
Cullinan Diamond
Cullinan I, or the Great Star of Africa, is a pendeloque-cut brilliant weighing and has 74 facets. It is set at the top of the Sovereign's Sceptre with Cross which had to be redesigned in 1910 to accommodate it. Cullinan I was surpassed as the world's largest cut diamond of any colour by the Golden Jubilee Diamond in 1992, but is still the largest clear cut diamond in the world. In terms of clarity, it has a few tiny cleavages and a small patch of graining. The diamond is fitted with loops and can be taken out of its setting to be worn as a pendant suspended from Cullinan II to make a brooch. Queen Mary, wife of George V, often wore it like this. In 1908, the stone was valued at US$2.5 million (equivalent to US$ million in )– two and a half times the rough Cullinan's estimated value.