The huge stone, weighing 709 carats, is reportedly one of the 20 largest ever found.
It was found by a pastor mining in Sierra Leone’s diamond-rich eastern province.
It is the largest diamond to be found in the country since 1972, when minors found the 969-carat ‘Star of Sierra Leone’.
The presidential spokesman said in statement that the diamond has not yet been valued.
But it will be sold in Sierra Leone with a “transparent” bidding process to the benefit of the community and country, the statement said.