The Centenary Diamond

The De Beers Centenary Diamond is, at 273.85 carats (54.77 g), the third-largest diamond to have been produced in the Premier Mine. The Centenary Diamond is rated in color as grade D color by the Gemological Institute of America, which is the highest grade of colorless diamond and is internally and externally flawless. It was named the Centenary Diamond as it was presented in the rough for the Centennial Celebration of De Beers Consolidated Mines on May 11, 1988. The Centenary Diamond was unveiled in final form in May 1991.

Discovery

The Centenary Diamond was discovered in the Premier Mine on July 17, 1986 using their X-ray imaging system. The original rough was 599 carats (120 g) and it was presented on May 11, 1988 in the Centennial Celebration of the De Beers Consolidated Mines. As then-chairman Julian Oglivie Thompson said, "We have recovered at the Premier Mine a diamond of 599 carats (120 g) which is perfect in color – indeed it is one of the largest top-color diamonds ever found. Naturally it will be called the Centenary Diamond."