Black diamonds have moved from the world of drill bits to the world of fine jewelry. In Basel, at The JCK Show in Las Vegas, and at the Jewelers of America show in New York, more dealers and manufacturers than ever before were displaying loose stones as well as black diamond jewelry. “I guess the popularity of black diamond has been increasing over the past five years or so,” says Kapil Seth of IBN Diamond in New York. He cites the platinum trend as one reason for black diamonds’ new vogue: “The white metal really contrasts the black of the diamond.” Jeff Curry, gemologist at the House of Onyx in Greenville, Ky., agrees that contrast is the key, but he sees it more in the juxtaposition of black diamonds with white diamonds in high-end fashion jewelry. Marcus Fuchs, manager of Chromagem in New York, cites a different reason for black diamonds’ popularity: “Black diamonds are fairly inexpensive, so you see a lot of caratage for fewer dollars.”
Fad, fashion, or forever? Is the black trend likely to have legs? “I don’t see the craze lasting very long,” says Alan Bronstein, a natural colored diamond dealer in New York. “People who wear black diamond have a certain personality. One needs to see the beauty in it for themselves, and a lot of people just don’t see it. They’re fascinated by the concept, but not to actually own one. That’s why black diamonds remain fairly inexpensive.”
Curry also doubts there’s a genuine trend. “I don’t think there’s any huge demand,” he says. “We sell mostly carat sizes to collectors.” George Solow of New York has been selling colored diamonds for 54 years. “There’s very little demand for black,” he says. “They want the yellows, the pinks, the blues.”
But Fawaz Gruosi, president of de Grisogono S.A. of Geneva and a leading designer of black diamond jewelry, has confidence in the new craze. In his book,The Black Diamond, he has this to say: “In the opinion of professionals like myself, black diamonds have long been underrated. In only two short years, in fact, the black diamond market has soared beyond belief. And this is only the start.”
What is black gem diamond? “The absorption of all the visible light across the visible spectrum is what makes natural black diamonds,” says Stephen Hofer, author ofCollecting and Classifying Coloured Diamonds. “No matter what impurities are in the diamond, the light-absorbing ability of these inclusions is very efficient at trapping all the light that falls on the stone and making it look black.” Hofer lists the common names given to pure black diamond as charcoal, gunmetal, ink, jet, midnight, onyx, pitch, steel, and wax.
Natural black diamonds are divided into two basic types. “Carbonados” derive their color from heavily included visible imperfections. “Pure black” diamonds have microscopic graphite dispersed throughout the gem. Both are black, but they’re physically and visually different.
Carbonados. Carbonado is the Brazilian name for black diamond. They’re heavily fractured and included and are considered industrial quality-also known as “crushing bort.” Carbonados are commonly pulverized and bonded to drill bits and other cutting tools. (It’s reported that carbonados were used to cut through rock during construction of the Suez Canal.) Their random crystal orientation makes them difficult to facet, but some black industrials can be polished and set into jewelry.
Pure black. The second-and rarer-type of black diamond resembles black onyx. “Those get their color from micro-dispersed graphite along the octahedral planes,” says John Koivula, chief research gemologist at the Gemological Institute of America. Unlike the industrial blacks, they’re not filled with eye-visible cracks lined with black inclusions. Because they’re not heavily fractured and not made up of twisted or randomly oriented crystals, they’re less difficult to facet than the industrial variety. Unfortunately, many people don’t note the difference between these blacks and the more common bort. “These very rare black diamonds are often lumped in with the much more common cracked stones,” says Koivula.
Quality grading black diamond. Because the best black diamonds are scarce, most faceted blacks are carbonados. Natural blacks are basically opaque but should be examined with a strong transmitted light. “Many black diamonds are highly included and show transparent near-colorless areas,” says Seth. These transparent spots reduce quality. “When choosing a black diamond, look for as black and as opaque as possible,” Seth adds. “The fewer the spots, the better it is.”
Finding the perfect black diamond may be impossible. In aGems & Gemology article titled “An Investigation of a Suite of Black Diamond Jewelry” (Winter 1990), Robert Kammerling, Robert Kane, Koivula, and Shane McClure reported that the black diamonds they examined “contained extensive cleavage/fracture systems that were lined with black inclusions.” Robert Aminzade of Natural Fancy Colored Diamond Company in Forest Lake, Minn., says, “Even the most-fine black diamonds have a little pit or scratch somewhere.” Close examination of black diamond jewelry bears out the verdict. At the shows, at least half the set stones I examined had eye-visible imperfections. With a loupe, the number was 75%.
Gruosi doesn’t see imperfection as a problem. “This is one of the charms of the black diamond,” he says. “It is not perfect.”
Issues of perfection aside, the finer-quality black diamonds-those with inherent color-are eagerly sought by high-end jewelry designers like de Grisogono. “Black diamonds which are caused from micro-dispersed graphite are actually mono-crystalline, not aggregate stones, and therefore have very few surface-reaching cracks,” notes Gruosi. “You can get a much more uniform color and polish, very similar to colorless diamond.” Gruosi seeks out the finer qualities. “We generally use the larger, more homogeneous stones as center stones, which means that a homogeneous pavé or center stone can be difficult to find, but we do it.”
What to pay for top-quality black diamond. Black diamond melee can cost as much as large single stones, if not more. Prices for treated goods in melee sizes are similar to prices for natural stones. “A decent one-carat might cost $250 per carat, the same as a parcel of 3-pointers,” notes Seth. He recently sold a 20-ct. blackish-gray diamond that showed red veining. “The finest stone I’ve ever sold was an 8-carater,” he says. It sold for $1,200 per carat.
Roger Basile, vice president of Grafstein’s in New York, says he hasn’t seen many nice natural blacks lately. His current stock-natural grayish blacks-is priced relatively low. “Typically they range from very cheap, at $100 per carat,” he says. Finer qualities and larger sizes can range up to $600 per carat. “We try to stay with the nicer material,” says Basile. “We look for tops which are very clean.”
But with black diamonds’ newfound popularity, the search for good quality at an attractive price is on. “Some dealers treat a lot of junk, and so it’s hard to be competitive,” says Basile. “We have to go through hundreds of goods, looking for clean tops and nice color to work with. We get a lot more calls for them than what we have.”
Curry sells both naturals and treated. Prices range from $400 to $500 per carat, but he says he hasn’t had any calls he can’t sell. Rahul Karnavat, president of Lotus Diagems in New York, says treated melee-1-pointers, for example-can cost up to $275 per carat. Four-pointers to 8-pointers cost from $175 to $250 per carat. Starbrillian.com is an Indian-Belgian firm that advertises black diamond prices over the Internet. The Web site quotes a full range of sizes from half-pointers through one-caraters. The smallest are the most expensive, $325 per carat. The remaining sizes range in price from $185 per carat to $275 per carat. All diamonds listed are advertised as natural color.
Aminzade says high-quality caraters range from $750 to $950 per carat. But fine stones can be priced even higher. Dror Yehuda of Yehuda Diamond Co. in New York says his family has been collecting black diamonds for three or four generations. “The largest stone we have is over 54 cts.,” he says. “We do sell black diamonds from a few carats on up. Typically they start at $1,500 per carat on a few carat-size stones. We have a pair of black dice, 22 cts. each, valued at $250,000.” Yehuda says the price depends on how black the stones are.
Seth warns that color and price aren’t the only factors to consider when buying black diamond. “Somebody told me that he bought a smaller parcel [thinking it was natural color], which turned out to be irradiated,” he says. With its almost metallic appearance, black diamond has inspired some fascinating fakes. Seth has even seen faceted gunmetal-actual metal-masquerading as black diamond.