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357-carat Rough Diamond From Prolific Letšeng Mine In Lesotho Nets $19.3m

This exceptional 357-carat rough diamond, which could easily be mistaken for a chunk of glacial ice, netted $19.3 million at Gem Diamonds' tender in Antwerp last week.


Unearthed in July at the famous Letšeng mine in Lesotho, the lucky find came on the heels of another sensational discovery —  a 314-carat diamond in May.

The Letšeng mine, which sits at an altitude of 10,000 feet in the tiny kingdom near the southern tip of Africa, has a long history of producing top-quality diamonds in huge sizes.


In fact, it's the highest-dollar-per-carat kimberlite diamond mine in the world. On the list of the 20 largest gem-quality white diamonds recorded since 2006, four were unearthed at Letšeng.

While there are always great risks associated with cutting huge rough diamonds, the world's top diamond traders bid aggressively to get their hands on these rare finds in the hope of creating the next museum-quality masterpiece. Due to the size of the rough diamond, it's very possible that it will be divided into a number of smaller stones.

In the case of the 507-carat Cullinan Heritage, for example, the rough diamond was expertly segmented into 24 D-flawless gems that were incorporated into head-turning necklace called "A Heritage in Bloom." The centerpiece of the necklace is a perfect 104-carat round brilliant.

Although it is not currently for sale, the necklace's value is estimated at more than $200 million. The original rough diamond had been purchased in 2010 for $35.3 million.

UK-based Gem Diamonds has maintained a controlling stake in the Letšeng mine since 2006. The Kingdom of Lesotho owns 30 percent. The mining company also boasts a 100% stake in the Ghaghoo mine in Botswana.