LSE-listed Petra Diamonds will hold a special tender for the sale of a 20.08 ct blue diamond recovered from the Cullinan mine, in South Africa, in September.
Viewings, which can be reserved via appointment, will take place from November 1 to 7 at Petra's diamond marketing offices in Johannesburg.
The tender will then follow from November 8 at the Diamond Exchange and Export Centre.
The tender will close on November 15 at 12:00.