A rough 2, 492-carat diamond, believed to be the second-largest has been unearthed in Botswana at Karowne mine ( 300 miles north Botswana’s capital, Gaborone) worth about £31million, owned by Canadian firm Lucara Diamond. The previous biggest discovery in Botswana was a 1, 758-caraat diamond found at the same mine in 2019. Botswana is one of the world’s biggest producer of diamonds about 20 per cent of global production.

Lucara’s head William Lamb, in a statement said “one of the largest rough diamonds ever unearthed”.

The biggest diamond in the world is 3,106-carat Cullinan diamond, found in south Africa in 1905  and cut into nine separate stones, many of which are in the British Crown Jewels.

Botswana’s government has proposed a law that will ask companies, once granted a license to mine, to sell a 24 per cent stake to local firms if the government does not exercise its option of becoming a shareholder.