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 Tiffany Yellow Diamond is one of the largest yellow diamonds ever discovered; its carat weight is 287.42 carats (57.484 g) in the rough when discovered in 1878 in the Kimberley mine in South Africa, and was cut into a cushion shape of 128.54 carats (25.108 g) with 82 facets—24 more than a traditional round brilliant—to maximize its brilliance. The facet pattern features eight needle-like facets pointing outward from the culet (bottom) facet. Jewelry and diamond historian Herbert Tillander refers to this as a 'stellar brilliant cut', and lists the gem in his book "Diamond Cuts in Historic Jewelry - 1381 to 1910" (1995) among other such diamonds: The Koh-I-Noor, the Polar Star, the Wittelsbach, among others.