The largest rough diamond discovered in more than 100 years is going on display in London.
It will be available to view for a week, before going to auction with Sotheby's.
According to experts, the stone could fetch more than $70,000 (£49,600). The gem is a 1,009 carat that was discovered last November in Botswana by a Canadian mining company.
It has been given the name 'Lesedi la Rona' which translates as 'our light' in Botswana's Swana language.
The rock is thought to be between two and a half and three billion years old.
The big question is whether or not the new owner of the stone will decide to leave it in its original form.
William Lamb, Lucara CEO, said: "The stone is older than life itself and it has so many different and unique qualities that make it a collector's item that I don't believe it should be polished, I think it is unique as it stands.
He added: "I would have the stone analysed, I would understand what the potential would be if I was going to polish it. But as it stands now I would keep it in its magnificent, unique form and I would not polish it."