Fifth biggest diamond found in mountains of Lesotho, Africa

By Thomas Biesheuvel

A small, embattled diamond miner just hit the jackpot. The 910-carat stone found by Gem Diamonds Ltd. high in the mountains of Lesotho in southern Africa is the fifth-largest in history. Here are the bigger ones:

Excelsior Diamond
Famed for its bluish-white color, the 995-carat Excelsior was found by a worker shoveling gravel at the Jagersfontein Mine in South Africa in 1893. Without a buyer, it was cut into at least 20 pieces, something one former De Beers executive called an unpardonable act. The largest of the cuts, the 70-carat Excelsior I, was bought for $2.6 million and now sits in a bracelet.

The Cullinan Diamond

Queen Elizabeth's Imperial State Crown (Image: Reuters)

By far the largest at 3,106 carats, it was found at the Premier mine in South Africa in 1905 and named after the mine owner, Sir Thomas Cullinan. Discovered just 9 meters (30 feet) below the surface and jimmied free with a pocket knife, the stone was given to King Edward VII as a birthday present before being sent to Antwerp to be cut into smaller gems.

The cutter was said to have fainted under pressure before dividing up the stone. The two biggest cuts -- the Great Star of Africa and the Lesser Star of Africa -- are set in the Crown Jewels of Britain.

The Lesedi La Rona

(Image: Sotheby's)

Found in Botswana by Canadian miner Lucara Diamond Corp. in 2015, the 1,109-carat Lesedi La Rona means “our light” in the local Tswana language. Roughly the size of a tennis ball, the fanfare surrounding its discovery soon soured when the stone failed to make its reserve at a Sotheby’s auction. It was eventually sold last year for $53 million, significantly less than the smaller 813-carat Constellation found at the same time. Jeweler Graff Diamonds currently owns the Lesedi.

The Star of Sierra Leone

The 969-carat diamond was found in Sierra Leone in 1972 and cut by Lazare Kaplan, the famous New York diamond firm headed by Maurice Tempelsman. Divided into 17 pieces, the largest had to be recut due to a flaw and the biggest totaled just 54 carats.

Gem Diamond’s latest discovery
Still without a name, the stone is about the size of two golf balls. It was found at the company’s Letseng mine, famous for the size and quality of the diamonds it produces and which has the highest average selling price in the world.

While Gem hasn’t yet said how it will sell the stone, analysts estimate it could fetch between $40 million and $50 million. Graff Diamonds founder Laurence Graff is Gem Diamond’s biggest shareholder and has bought many of its large diamonds.