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.
The Jonker
The Jonker diamond was found at the Elandsfontein mine in South Africa by Johannes Jacobus Jonker on 17 January 1934. The diamond was 726 carats, which at the time was the fourth largest uncut gem ever found. The diamond was found 5 km away from the largest diamond ever found, the Cullinan Diamond. There is speculation that the Jonker may have originally been part of the Cullinan crystal, as both crystals had cleaved faces which seemed to match up perfectly.