A Christian pastor working in a Sierra Leone mine has found a 706-carat diamond, which could be the tenth largest ever found.
The precious stone was found by Emmanuel Momoh, who was working in the Kono region, in the east of the country.
It will be sold in Sierra Leone in a 'transparent' bidding process to benefit the country, according to a government statement.
It read: 'A 706-carat diamond was presented to President Dr Ernest Bai Koroma yesterday evening.
'Receiving the diamond President Koroma thanked the chief and his people for not smuggling the diamond out of the country.'
Diamond expert Paul Zimnisky said it could be 'between the 10th and 15th largest gem-diamonds ever recovered' and such a find is very rare in a small mine.
He said: 'Most recent exceptional diamond discoveries have been made by large commercial miners that mine very large volumes of kimberlite ore and process it with advanced equipment.
'Artisanal mining tends to produce smaller, lower quality diamonds because the diamonds suffer breakage and erosion.'
Zimnisky said the stone would likely be sold outside Sierra Leone, despite the government's assertion, for better access to buyers.
Without a professional assessment of the diamond's potential flaws and colouring it is impossible to value the stone.
However, a polished stone cut from the Jonker, which is the 10th largest gem-diamond ever recovered until now at 726 carats, will go on sale in Hong Kong in May.
A single 25-carat portion is likely to sell for $2.2 million to $3.6 million (£1.78 million to £2.75 million), or $88,000 to $144,000 for a single carat, Zimnisky said.
A 1,111-carat diamond was discovered at a mine in Botswana in 2015, the biggest find for more than a century.
That gem is second in size only to the Cullinan diamond which was unearthed in South Africa in 1905, at 3,106 carats uncut, according to the Cape Town Diamond Museum.
The Cullinan was cut into several gems, including two set into the sceptre and crown of the British Crown Jewels.
Historically, Sierra Leone has had a controversial role in the diamond industry.
The sale of 'blood diamonds' helped finance civil wars across Africa in the 1990s and often funded military dictatorships on a continent that the London Diamond Bourse estimates provides 65 percent of the world's diamonds.
Rebels allowed traders to exploit diamond mines and ship the gems abroad via Liberia.
In one of the most notorious cases, former Liberian warlord Charles Taylor was found guilty of supporting the rebels in exchange for diamonds mined by slave labour.
The district where the 706-carat diamond was discovered is where US-Belgian businessman Michel Desaedeleer, accused of enslavement and diamond trafficking during Sierra Leone's civil war, is alleged to have committed his crimes.
Music: "Artifact" Kevin MacLeod (incompetech.com)Licensed under Creative Commons: By Attribution 3.0 License http://creativecommons.org/licenses/by/3.0/