James Allen News Center

Miners in the African nation of Lesotho reported discovering a 478-carat diamond – the 20^th largest rough diamond ever found.

It`s not just the pure carat weight that`s impressive: the diamond has a D color grading, which is the highest possible color rating for a white diamond.  A preliminary analysis of the stone was conducted by experts in Antwerp, Belgium.  So far, there are no visible inclusions in rough form – a rare feat even for diamonds that are mere fractions of its size.

Experts said that there`s a good chance of getting a 150-carat plus round stone with the highest color and clarity rankings, which would make it the first in the history.  It could sell for tens of millions of dollars, making it one of the most valuable diamonds ever to be found.

The diamond was discovered in the Letseng Mines, which is co-owned by Gem Diamonds and the Kingdom of Lesotho.  The mines are no stranger to record-breaking diamonds: 603-carat and 493-carat diamonds were found there in 2006 and 2007. 

The 603-carat diamond, known as the "Lesotho Promise," was bought by the South African Diamond Company and fashioned into twenty-six separate diamonds, including seven pear-shaped diamonds, four emerald cuts, thirteen round brilliants and one heart-shaped diamond.

The 601-carat "Lesotho Brown" diamond was discovered at the Letseng Mines in 1960 and was later fashioned into 18 separate diamonds.