Debswana, a Botswana diamond company, announced the discovery of a 1,098-carat stone, the world's third largest of its kind.
The company's acting managing director, Lynette Armstrong, handed the stone, which was discovered on June 1 to the country's president, Mokgweetsi Masisi, on Wednesday.
It is the world's third largest, behind the 3,106-carat Cullinan discovered in South Africa in 1905 and the 1,109-carat Lesedi La Rona discovered in Botswana in 2015.
"This is the largest diamond to be recovered by Debswana in its history of over 50 years in operation," Armstrong said.
The yet-to-be-named stone, which is 73mm long, 52mm wide and 27mm thick, is also the largest gem-quality stone discovered in the history of Debswana, a joint venture between the government and global diamond giant De Beers.
Armstrong said no decision had been made on whether the "rare and extraordinary stone" will be sold through De Beers or the state-owned Okavango Diamond Company.
Botswana is Africa's largest producer of diamonds.
The discovery of the stone, according to Minerals Minister Lefoko Moagi, could not have come at a better time after the Covid-19 pandemic devastated diamond sales in 2020.
The government earns up to 80% of Debswana's sales revenue in the form of dividends, royalties and taxes.
As a result of the pandemic, production at the business fell 29% in 2020 to 16.6 million carats, while sales decreased 30% to $2.1 billion.
Debswana plans to boost output by up to 38% to pre-pandemic levels of 23 million carats in 2021, when the global diamond market recovers with the easing of travel restrictions and the reopening of jewelers.