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.
National Museum of Natural History
The National Gem and Mineral Collection is one of the most significant collections of its kind in the world. The collection includes some of the most famous pieces of gems and minerals including the Hope Diamond and the Star of Asia Sapphire, one of the largest sapphires in the world. There are currently over 15,000 individual gems in the collection, as well as 350,000 minerals and 300,000 samples of rock and ore specimens. Additionally, the Smithsonian's National Gem and Mineral Collection houses approximately 35,000 meteorites, which is considered to be one of the most comprehensive collections of its kind in the world.