The Centenary diamond

The world’s largest top-color diamond

The Centenary Diamond was recovered at Premier Mine (DeBeers) in times od centenary celebrations of DeBeers, hence it beautiful name. The raw diamond was perfect 599 carat, The Centenary was found on July 17th, 1986 by the electric X-ray recovery system at the Premier Mine and it’s presence was kept as Top Secret.

No more fitting way of celebrating 100 years of achievement by De Beers could have been devise than the discovery of such a diamond and nowhere was it more likely to have been recovered than at the Premier Mine. Over the years this extraordinary mine has produced several outstanding diamonds of the most superb color, which have been cut into famous gems: The Cullinan in 1905; the Niarchos in 1954; the Taylor-Burton in 1966 and the Premier Rose in 1978. Now that the second millennium has ended, it is interesting to reflect that only nineteen gem-quality diamonds larger than the Centenary rough have been found during its course. The Premier Mine itself has produced nearly three hundred stones weighing more than 100 carats, and a quarter of the world’s diamonds weighing more than 400 carats.

Cutting the Centenary

For a long year Tolkowsky , man responsible for this difficult task he examined the stone stone until he knew every fissure and crevice of it. Using the most sophisticated electronic instruments he gazed deep into the crystal structure. “From the moment I knew I was going to cut it,” he said, “I became another man. A strange man. I was looking at the stone in the day, and the stone was looking at me at night.”

The first step before the diamond could be faceted was the elimination of large cracks from the edge of the stone running a considerable depth inside it. He decided not to saw or cut with a laser because both methods would heat or vibrate the diamond. Instead, he turned to the time-honored method of kerfing by hand. It took Tolkowsky 154 days to remove about 50 carats which otherwise would have been polished to dust. At the end was a roughly-shaped rounded crystal about the size of a bantam’s egg, weighing about 520 carats. After that was an endless process of drawing and measuring as possible shape designs began to emerge. In all, thirteen different designs were presented to the De Beers board, with the strong recommendation they should chose a modified heart shape. Once this recommendation had been accepted, the final process of faceting the Centenary began in March, 1990. By January, 1991 it was nearing completion.

When cutting was completed the Centenary weighed 273.85 carats, measured 39.90 × 50.50 × 24.55 mm, and had 247 facets - 164 on the stone and 83 around its girdle. Never before had such a high number of facets been polished onto a diamond. In addition, two flawless pear shapes weighing 1.47 and 1.14 carats were cut from the rough. Amoung top-color diamonds the Centenary is surpassed only by the Cullinan I (aka the Star of Africa) and the Cullinan II, which were cut from the Cullinan crystal before modern symmetrical cuts were fully developed in the 1920’s, making the Centenary the largest modern fancy cut diamond in the world and the only one to combine the oldest methods - such as kerfing - with the most sophisticated modern technology in cutting. The Cullinan diamonds are actually near-colorless, but qualify as white diamonds. The GIA color grading letters D, E and F qualify as colorless, and the Centenary is the best of the three - a ‘D’. This spectacular gem, which has become the ultimate example of those qualities was shown to the world for the first time in May, 1991. Mr. Nicholas Oppenheimer, then Deputy Chairman of De Beers rightly declared “Who can put a price on such a stone?” confirming that it was insured for around $100 million.

Whether the Centenary Diamond has since been sold is a mystery.

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