(CNN) -- A diamond unearthed in the southern African nation of Lesotho could yield one of the largest and highest quality round polished diamonds, according to a statement Monday from company that found it.



A mining company unearthed this 478-carat diamond in the southern African nation of Lesotho.



Experts in Antwerp, Belgium who analyzed the 478-carat stone determined it to be of the highest color grading available for a white diamond, said a statement from Gem Diamonds Ltd., the company that found the stone.



"What makes it more remarkable is the color and quality of this stone," said diamond consultant Neil Buxton.



"It's a D color, which is the highest possible graded color you can get, and we believe there is a chance -- a very good chance -- of getting a 100-carat plus" round stone with the highest color and clarity rankings.



The company said such a stone would "to the best of our knowledge" be "the first one in history."  Watch more on the diamond »



The diamond, which was found in September, ranks as the 20th largest rough diamond ever found, but is not the biggest ever taken from the Letseng Mine, which is co-owned by Gem Diamonds Ltd. and the Kingdom of Lesotho, a country of 2.1 million that is surrounded by South Africa.



Two bigger stones -- 603 and 493 carats -- were found in the mine in 2006 and 2007, respectively, the company said. A 601-carat diamond was mined there in 1960, it said.
( CNN ) -- A diamond unearthed in the southern African nation of Lesotho could yield one of the largest and highest quality round polished diamonds , according to a statement Monday from company that found it . A mining company unearthed this 478-carat diamond in the southern African nation of Lesotho . Experts in Antwerp , Belgium who analyzed the 478-carat stone determined it to be of the highest color grading available for a white diamond , said a statement from Gem Diamonds Ltd. , the company that found the stone . " What makes it more remarkable is the color and quality of this stone , " said diamond consultant Neil Buxton . " It 's a D color , which is the highest possible graded color you can get , and we believe there is a chance -- a very good chance -- of getting a 100-carat plus " round stone with the highest color and clarity rankings . The company said such a stone would " to the best of our knowledge " be " the first one in history . " Watch more on the diamond » The diamond , which was found in September , ranks as the 20th largest rough diamond ever found , but is not the biggest ever taken from the Letseng Mine , which is co - owned by Gem Diamonds Ltd. and the Kingdom of Lesotho , a country of 2.1 million that is surrounded by South Africa . Two bigger stones -- 603 and 493 carats -- were found in the mine in 2006 and 2007 , respectively , the company said . A 601-carat diamond was mined there in 1960 , it said .
What is the carat weight of the gem?
What is the carat weight of the gem ?
478-carat
478-carat