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.
Tiffany Yellow Diamond
The gem was on loan from Tiffany & Co. to the Smithsonian National Museum of Natural History in Washington D.C. and was on display from April 18, 2007 until September 23, 2007. At the time, Jeffrey E. Post, the museum`s gem curator, said that this was the largest diamond on display in the U.S. The famous Hope Diamond is only 45.5 carats, which is about one-third the mass of the Tiffany Yellow Diamond.