Freetown- A pastor working in the mines of eastern Sierra Leone has unearthed a 706-carat diamond.

The diamond was presented to President Ernest Bai Koroma late Wednesday before being locked in Freetown’s central bank vault. It awaits an official valuation under the Kimberley Process, which certifies diamonds as “conflict-free”.

It will then be sold in Sierra Leone under a transparent bidding process, a government statement said, thanking the chief of the Tankoro area where the stone was found for not smuggling it out of the country.

Without a professional assessment of the diamond’s potential flaws and coloring it is impossible to value the stone.

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.