World's second-biggest diamond unearthed in Botswana

Canada's Lucara Diamond Corp has discovered a 2,492 carat diamond at its Karowe mine in Botswana, the company said, making it one of the largest stones ever to be excavated.

Lucara did not reveal the stone's gem quality but its size would make it the second largest rough diamond discovered to date, after the 3,106 carat Cullinan Diamond found in neighbouring South Africa in 1905. After being cut and polished, it became part of the British crown jewels.

The Karowe Mine is known for producing large stones, with other significant finds including the 1,758 carat Sewelô and the 1,109 carat Lesedi La Rona diamonds.

The company will present the diamond to Botswana's President Mokgweetsi Masisi on Thursday. Botswana is the world's top diamond producer by value.

The southern African country last month proposed a law that will ask mining companies, once granted a license, to sell a 24 per cent stake in mines to local investors unless the government exercises its option to acquire the shareholding.