Prolific Letšeng Mine Bears Another Massive Diamond; 198-Carat ‘Exceptional’ Rough Gem Could Fetch $15 Million

The prolific Letšeng mine in the tiny African Kingdom of Lesotho just yielded another massive rough diamond — a 198-carat shimmering stunner the size of a large strawberry. Experts expect it to sell for as much as $15 million.

Officials for Gem Diamonds Limited, which owns a 70 percent stake in the mine,
described the stone as an “exceptional white, high-quality diamond [that] displays no florescence.” It has a Type IIa rating, which means it is chemically pure and has an exceptional optical transparency.

"The recovery of this large, high-quality white diamond continues to support the Letšeng mine's reputation as the most important source of exceptional quality, large diamonds," Gem Diamonds CEO Clifford Elphick said in a statement.

In fact, five of the 20 largest gem-quality white diamonds ever recorded were unearthed at the Letšeng mine — a mine in the kingdom's northern Maluti mountains that consistently yields the highest per-carat value of any kimberlite diamond mine in the world.

In 2001, Gem Diamonds pulled a 553-carat rough white diamond from Letšeng, and a just over a year ago the company extracted a gem-quality rough white diamond weighing in at 164 carats. That stone was eventually sold for $9 million.

London-based mining analyst Martin Potts told National Jeweler that he expects the recently discovered 198-carat stone to fetch between $12 million and $15 million.

Gem Diamonds has owned a controlling stake in Letšeng since 2006. The Kingdom of Lesotho owns 30 percent. The diamond mine is one of the highest in the world, sitting at an altitude of 10,000 feet.

Diamond photo via Gem Diamonds; Mine photo via et-global.com/uncredited