In November 2015, Lucara Diamond Corp. announced that they recovered an extremely large, high-quality diamond from their Karowe Mine in Botswana, Africa.
Dubbed “Karowe AK6,” the gem measures 65mm x 56mm x 40mm (almost as big as a tennis ball) and weighs 1,111 carats (about 7.8 ounces) – making it the largest diamond to be found within the last 100 years, the largest diamond ever found in Botswana, and the largest diamond ever recovered using machines (Lucara CEO, William Lamb said that had the diamond not been discovered with the latest technology, it might have been passed over and ground up with other waste stones). Overall, Karowe AK6 the second-largest gem quality diamond ever found (or third largest, if you are counting non-gem quality diamonds).
In addition to its size, Karowe AK6 is also stunningly beautiful – earning a “Type IIa” classification. Type IIa diamonds make up 1–2% of all natural diamonds (1.8% of gem diamonds) and are almost or entirely devoid of impurities, such as hydrogen, nitrogen, or carbon. Other famously large diamonds, like the Cullinan (Great Star of Africa) and Koh-i-Noor (Mountain of Light) are also Type IIa.
As for the value of the stone, that remains to be determined. Former diamond-mining geologist Phil Swinfen estimates that once the diamond is cut and graded, it could have a valuation around $40–60 million.