Another large diamond has been found at the Letseng mine in Lesotho, a small kingdom in South Africa.
The stone weighs 478 carats and is the 20th largest rough diamond ever found and it may become the largest ever polished round diamond.
Another similar sized rough stone from the same mine was recently valued at $12million. But the clarity and round shape of the new gem mean it could be worth considerably more and in its polished state could sell for tens of millions of dollars.
A spokesman for Gem Diamonds, who own the mine, added that initial examination suggested that the white diamond, which has yet to be named and valued, has a completely flawless centre.