Petra Diamonds
The Cullinan mine continues to produce large stones. The Cullinan Heritage, a white diamond, was discovered in September 2009. This stone was the 19th biggest uncut diamond ever found and was sold in February 2010 to Chow Tai Fook Jewellery for $35.5m, the highest price ever paid for an uncut diamond. The previous record was held by Gem Diamonds' Leseli La Letšeng, which was bought for $18.4m by Graff Diamonds in December 2008.
Merlin diamond mine
The Merlin mine has an unusually high proportion of gem-quality diamonds: 65% of production is gem-quality, and only 35% is classified as near-gem or industrial quality. This compares to a worldwide average of just 20% gem-quality diamond production at diamond mines worldwide, and a mere 5% gem-quality production at Australia's largest diamond mine, Argyle diamond mine. The high ratio of gem-quality diamonds is responsible for a relatively high value of $108 USD per carat (540 $/g). The known ore grade at Merlin is about 0.2 carats (40 mg) per tonne, although exploration continues under the mine's new owner. The largest diamond produced at the Merlin mine measured 104.73 carats (20.946 g), the largest ever found in Australia, and has been valued at over US$525,000 .