Shares in Africa-focused Gem Diamonds (LON:GEMD) jumped as much as 6.5% on Wednesday after the miner revealed it had dug up yet another big rock at its flagship Let??eng mine in Lesotho.
The 169-carat, top white colour, Type IIa rock is seventh diamond of over 100 carats the company has recovered so far this year at the mine, the world's highest dollar per carat.
The finding comes barely a day after Gem Diamonds sold a 910-carat rock, the "Lesotho Legend", for $40 million at auction. The stone, the size of about two golf balls, is the world's fifth biggest gem-quality diamond ever found.
So far this year, the company has found as many diamonds as the total for the whole of 2017 at its Letseng mine in Lesotho.Gem Diamonds stock gained 6p to 99p in London at 8:20AM to close 3.66% higher at 93p.
The company also reported Wednesday earnings before interest, tax, depreciation and amortisation of $48.6m for 2017, down 22% from a year earlier, hit by the costs of momentarily closing its Ghaghoo mine in Botswana due to an earthquake.
Since acquiring Let??eng in 2006, Gem Diamonds has found now five of the 20 largest white gem quality diamonds ever recovered and several 100-carat-plus stones
At an average elevation of 3,100 metres (10,000 feet) above sea level, Let??eng is also one of the world's highest diamond mines.
The biggest diamond ever found was the 3,106-carat Cullinan, dug near Pretoria, South Africa, in 1905. It was later cut into several stones, including the First Star of Africa and the Second Star of Africa, which are part of Britain's Crown Jewels held in the Tower of London. Lucara's 1,109-carat Lesedi La Rona was the second-biggest in record, while the 995-carat Excelsior and 969-carat Star of Sierra Leone were the third- and fourth-largest.