Silks of London

Coloured diamonds - an insider's guide

In November 2010 a 24.78-carat pink diamond sold at a Sotheby’s auction in Geneva to diamond dealer Laurence Graff for a record $46.1 million, the highest price paid for any gem or jewel—ever. That was nearly double the previous record of $24.3 million set in 2008 at a Christie’s sale in London, when Graff purchased another legendary stone: a 35.56-carat blue diamond called the Wittelsbach. Prices for coloured diamonds have gone through the roof over the last few years!

In 2009, a five-carat pink diamond sold at Christie’s in Hong Kong for $10.8 million, achieving a world record price per carat of $2.1 million. In October 2010, the Bulgari Blue, a ring with a triangular-cut, 10.95-carat blue diamond, sold at Christie’s New York for $15.7 million, setting a new record price per carat for a blue diamond. And in November 2010, a 14.23-carat pink diamond fetched $23.1 million at Christie’s Hong Kong, the highest price ever paid for a jewel at auction in Asia.  Last year, Christie’s worldwide jewelry sales totaled $426.4 million, an all-time high that led the house to declare 2010 the year of colored diamonds.  Of the millions of diamonds mined each year, the gem industry estimates that one in every 10,000 carats will possess color. Only a handful of those achieve the deeper, more valuable hues described in the industry as “fancy intense” and “fancy vivid.” Of those, an even smaller percentage surpass one carat, let alone five or ten! So you can see how rare these stones!

According to Naval Bhandari of Sotheby’s Diamonds, since record keeping began in the 1970s, colored diamonds have appreciated at about 10 to 15 percent per year. “Yellow diamonds have doubled in value every seven years,” he says. “Reds, blues and greens have seen the greatest appreciation, having quadrupled within the last decade.” 

Robert May, executive director of the Natural Color Diamond Association, cites the growing affluence in emerging markets, like Russia, India, South America and China, as a major factor. “There’s a whole new body of consumers,” he says. “Asia really likes colored diamonds, and they have significantly driven up the price.”

Experts say a watershed moment in the public’s awareness of colored diamonds occurred in 1987, when a .95-carat red diamond fetched $880,000 at Christie’s New York, making headlines around the world. Reportedly purchased for $13,500 in 1956 by Montana gem collector Warren Hancock, the Hancock Red set a new record of nearly $1 million per carat, a benchmark that held until 2007.

With the increased visibility of colored diamonds comes a whole new vocabulary. In the ’40s and ’50s, the Gemological Institute of America developed the universal grading system known as the 4Cs, examining carat, color, clarity and cut to evaluate white diamonds. When shopping for colored diamonds, however, the 4Cs become more complex. In 1995, the GIA expanded its system to measure hue, tone, saturation and distribution of color in colored diamonds. “Hue” describes, well, the color and can include a modifier such as purplish-pink. “Tone” refers to the stone’s lightness or darkness, and “saturation” implies strength or purity of color.  The scale begins with “faint” and moves up to “light,” “fancy light,” “fancy,” “fancy intense” and “fancy vivid,” the last the most valuable. (While fancy colored diamonds do occur naturally, there is also a sizable market for treated and synthetic stones that mimic them—especially in pink, yellow and green diamonds of late. Fortunately, labs can easily identify most treatments and almost all synthetic manufacturers mark their stones for full disclosure.)

So exactly how and why do some diamonds come out looking like a ruby or a sapphire? Colored diamonds result when natural radiation or trace elements such as nitrogen interact with carbon atoms during formation, yielding literally every color of the rainbow. Hues like yellow and brown are more abundant. Purple, orange, green and red are the rarest. “Many jewelers will never see a red diamond in their career,” says Bhandari. John King, GIA Laboratory’s chief quality officer, agrees: “To say a red diamond is one in a million is certainly no stretch.” In fact, the largest natural fancy red diamond known to exist is a relatively diminutive 5.11 carats and is owned by Moussaieff Jewelers in London. It is not for sale.

Silks of London

SoL has worked with coloured diamonds for years.  We have recently designed a stunning yellow diamond engagement ring which will soon be on our website! www.silksoflondon.com

Source: www.departures.com