Some of the most important fancy colored stones sold at auction come from the depths of bank vaults. Estate jewellery is a small but prestigious source of extremely fine fancy colour diamonds, according to Gary Schuler, director of Sotheby’s New York jewellery department. “Yes,” he says, “people are coming in with things from their vaults. Those are our most desired sources. They’re fresh to the market, attractive, with interesting cutting.” The supply is small, however, he adds, because “There were not very many people 40 to 50 years ago who were acquiring colored diamonds. It took a real connoisseur to appreciate those diamonds. It is not a regular occurrence but some of the greatest colored diamonds have come to us this way.”

When they do, Schuler explains, they are often truly impressive because “In the old times, colored diamonds were cut the same as white diamonds.” The round brilliant cut is ideal for a white or colourless diamond; it enhances the lack of colour by increasing reflection. Fancy colour diamonds, on the other hand, are rarely fashioned into round brilliants. That’s because, Schuler says, they are shaped by cutters “to draw colour to the middle of the stone, to brighten it up.” When a round fancy colour diamond comes to market, he says, “You are seeing material with rich saturation. Only the best material was cut and used in jewellery.” During that era, dealers and jewellers simply did not use material that was not fully saturated.

A dazzling example of a treasure from a vault is a vivid blue pear shape, shown on the opposite page, from the estate of Mrs. Paul Mellon that is slated to come to auction at Sotheby’s New York on November 20, 2014. Schuler says the stone “was cut around the 1950s or 1960s; there was no record of it in the family. It’s a 9.75-carat VVS2 potentially flawless fancy vivid blue. What is so alluring is that it is cut like a white diamond with saturation of colour and beauty.” The blue was originally matched with a 9-carat fancy blue, the pair set as ear pendants, but the vivid blue is being offered on its own.

In addition to the high flyers, auctions offer stones at the lowest end of the Gemological Institute of America (GIA) D to Z colour grading scale, diamonds that are graded X, Y or Z. These are of interest to diamantaires who see the potential for recutting, bringing out more of the yellow, turning them into fancy light yellow diamonds.

The future of fancy colour diamonds rests almost entirely in the hands of Rio Tinto. No firm decision has been made about continuing beyond 2020 its underground operation at Argyle, the world’s largest supplier of colored diamonds. But whenever this mine closes, it will be a game changer for the colored diamond category. At that point, barring any other source being discovered, fancy colour diamonds likely will revert to the rarities they always were: singular, unique stones produced on rare occasions by mines around the globe.

Article from the Rapaport Magazine – October 2014. Author: Ettagale Blauer