Africa-focused Gem Diamonds (LON:GEMD) is having an extraordinary year so far as the small miner continues to find precious rocks bigger than 100 carats at its flagship Let??eng mine in Lesotho.
On Wednesday, the England-based company said it had dug up a 152-carat, top white colour type IIa diamond, the sixth major find so far this year.
In contrast, it discovered only seven diamonds bigger than 100 carats for the whole of 2017 and five the year before.
Shares in the miner, which in January scored big by finding the world's fifth-largest diamond in history, jumped moderately on the news. They were up 1.3% to 86.50 pence by 12:57 PM local time.
Since acquiring Let??eng in 2006, Gem Diamonds has found about five of the 20 largest white gem quality diamonds ever recovered, which makes the mine the world's highest dollar per carat kimberlite diamond operation.
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.