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.
McPherson College
In 1926, J Willard Hershey synthesized one of the world's earliest synthetic (man-made) diamonds on the McPherson College campus. Reporting on his experiments, Hershey wrote, "Since we first began our experiments in their manufacture more than 50 diamonds have been made synthetically at McPherson College, ranging in size from the smallest, one millimeter (about 1/25 inch) in diameter, to the largest, which, is two millimeters by one and one half millimeters by one millimeter, weighing 1/30 carat." One of the diamonds is on display at the McPherson Museum in McPherson, Kansas. There is some debate about the success of Hershey's experiments, with some researchers concluding that the diamonds were not true diamonds and others concluding that some of them were.