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.
Royal Asscher Diamond Company
In 1903, at , the Excelsior diamond was the largest diamond ever found. The gem required expert handling to be properly carved: inclusions within the rough diamond prevented it from being polished as a single stone. Abraham Asscher was charged with cleaving the Excelsior; to minimize flaws, he carved the stone into ten diamonds which were primarily sold to anonymous purchasers. Rumor and myth abound regarding the location of the diamonds.