Luxury jeweller Graff has acquired the 14th largest diamond ever mined - the Peace Diamond - for $6.5m (£4.8m).
The global diamond trading network that handled the auction, the Rapaport Group, said the stone had gone to British billionaire and jeweler, Laurence Graff.
The egg-sized, 709-carat "Peace Diamond" is one of the largest ever discovered in Sierra Leone and between the 10th and 15th largest ever found. Named the Peace Diamond, $3.8 million of the proceeds will directly benefit 250,000 inhabitants of a region with no school, hospital, clean water, roads or electricity.
The Peace Diamond is on display at the Rapaport Group on December 4, 2017 in midtown NY. In many cases, groups used slave labor to mine the stones.
The United Nations lifted a ban on diamond exports from Sierra Leone in 2003, though the $113 million sector is plagued by smuggling.
An earlier bid of $7.8m was rejected by the government when the stone was initially auctioned in Freetown, after it said that the figure was too low. "At this moment, the story of this diamond marks an important chapter for the people of Sierra Leone", Graff adds.
"It will encourage all the diggers back home", said Chief Paul Ngaba Saquee, head of Sierra Leone's eastern Kono district where the diamond was found.
According to the statement, the Sierra Leone government lost a little more than $500,000 after declining a bid of $7.08 million back in May.