The Jwaneng mine, the richest in the world, recently celebrated its 25 years in Botswana. The mine holds resources that produce up to 15 million carats a year, and is especially popular for its blue diamonds.%%"When these gemstones are cut and polished, they produce eight million pieces of jewellery in a year. This means over the last 25 years Jwaneng mine's diamonds have been worn by over 100 million customers all over the world", said Gareth Penny, chief executive of De Beers.%%The Jwaneng mine contributes to 70% of the annual earnings of all the four Debswana diamond mines, a 50/50 partnership between the government of Botswana and De Beers. It is scheduled to move to underground mining in 2012, and according to Penny, the increased costs of diamond mining pose a problem in Botswana.