Laurence Graff, the British billionaire jeweler known as the king of diamonds, wanted to own the rock, all 603 carats of it, the moment he hung up the phone last August. The conversation was brief: The Lesotho Promise, the 15th-largest rough diamond on record, had just been excavated at the Letseng Diamond Mine in Lesotho, a tiny, mountainous kingdom landlocked within central eastern South Africa. For a man of Graff’s temperament and ambitions (“I’ve never said no to a diamond,” he says with typical swagger), the opportunity to own a gem of such proportions was utterly tantalizing. Fascinating in its original mined state, the staggering stone could prove a massive windfall for the jeweler, via its potential offspring—many smaller “satellite” diamonds.
Over the years, Graff has owned many extraordinary rocks, perhaps more than any other jeweler in business today. Just last November he scooped up the 493-carat
Letseng Legacy, which hailed from the same pit as the Promise, once again proving his insatiable lust for massive stones. Other notable Graff diamonds include the 100-carat Star of America, the 137-carat Paragon, the 132-carat Sarah and many 50-plus-carat diamonds.
Still, a rough diamond larger than the Promise hadn’t surfaced since the discovery of the 777-carat Millennium Star in the Democratic Republic of Congo in 1993. In addition, the Promise was a beautiful white D-grade color, the most valuable on the calibrating system. And, quite simply, Graff had never owned a rock that big.
While small diamonds, the kind that dapple watches or engagement rings, are hardly scarce, the discovery of a 200-carat-plus rough diamond typically generates headlines. The past couple of years have yielded several large stones—many of them from Letseng. In addition to the Promise and the Legacy, a 215-carat rough diamond mined there last March was sold to Omega Diamonds for $8.3 million. Of course, all of those would be dwarfed by the Cullinan. The largest diamond on record, the Cullinan was unearthed in South Africa in 1905 and weighed in at a monstrous 3,106 carats. But experts are skeptical whether equally impressive diamonds will continue to emerge. As Graff USA president and CEO Henri Barguirdjian puts it, “Finding another stone like the Lesotho Promise is the equivalent of finding a van Gogh that has been lost for a century.”
Barguirdjian would get no argument from the mine worker who first set eyes on the Promise. “She was alone in the sorting room, and she started screaming,” relates Clifford Elphick, chief executive of Gem Diamonds Ltd., which operates the Letseng mine with the government of Lesotho. “People came running. They thought she’d been electrocuted.”
De Beers operated Letseng, which excavates an average of 250 carats per day, until 1982, when it was shuttered after the U.S. recession triggered a downturn in the diamond market. Since Gem Diamonds took ownership in 2006, the mine has experienced a major hot streak, cornering the market on enormous stones.