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.
Economy of Botswana
Since the early 1980s, the country has been one of the world's largest producers of gem diamonds. Four large diamond mines have opened since independence. De Beers prospectors discovered diamonds in northern Botswana in the early 1970s. The first mine began production at Orapa in 1972, followed by a smaller mine at Letlhakane. What has become the single richest diamond mine in the world opened in Jwaneng in 1982. The mine was discovered when termites looking for water brought grains of diamond to the surface. Botswana produced a total over 30 million carats (6,000 kg) of diamonds (about 25% of worldwide production) from the three Debswana mines in 1999, and is the highest producer of diamonds by value in the world. According to Debswana, the Orapa 2000 Expansion project increased the Orapa's mine annual output from 6 million carats to 12 million carats and raised total production to 26 million carats. In 2003, Debswana opened the Damtshaa diamond mine about 220 kilometres (140 mi) west of the city of Francistown. The mine was placed into care and maintenance in December 2015 due to weak global demand but was scheduled to reopen in January 2018.
In 2008, Australia's Kimberley Diamond Company opened a mine in Lerala, Botswana's fifth mine and the first not operated by Debswana. However, Kimberley shut down the mine in May 2017, citing weak market conditions.