With a Tweak and a Smile

March 1999

Diamonds:Gemology

With a Tweak and a Smile

Synthetic diamonds of color present new opportunities for designers and manufacturers. They also present new identification challenges

Roll out the welcome mat for synthetic diamonds with a tweak: colors that include exotic reds and pinks. Jewelers and designers concerned about affordability or availability will welcome the commercial debut of these colors. But they'll also need to develop a plan regarding proper identification.

Markets have long been roused by natural red diamonds. New York City dealer William Goldberg sold a 5.11-ct. natural red diamond for nearly $1.9 million per carat last year, for example. But the extreme rarity of natural reds can prevent even those who can afford to from owning one.

The new red synthetic diamonds are one solution.

Challenge of Supply
Colored synthetic diamonds called Ultimate Created Diamonds are scheduled to debut this spring, made in Russia and marketed by Alex Grizenko of Ultimate Created Diamonds Co., Boulder, CO.

Prices will vary by size and color. While all synthetic diamonds are a challenge to produce, he says, orange, peach, pink and red are more challenging than others and will cost more. Red synthetics, for example, will sell for $3,000 to $5,000 per carat, far below the natural red diamond mentioned above. "We want to have hundreds of carats of red diamonds in the 0.30-0.60-ct. range available this spring," says Grizenko. "Our goal is to be able to supply the market with nice little rows of even colors."

Larger stones up to 2 carats polished will be available also, but they will cost more.

Challenge of Identification
As these synthetic diamonds, particularly the small ones, are set in jewelry, the need for proper identification – and disclosure – will increase dramatically. For this reason, Grizenko has arranged for the Gemological Institute of America to laser-inscribe the Ultimate Created Diamonds logo and an inventory number on his products in sizes above 0.10 carat (he doesn't plan to sell melee).

Synthetic red diamonds from Ultimate Created Diamonds Co., Golden, CO, will enter the market this spring. This one is 1.16 carats. Courtesy of Ultimate Created Diamonds, Boulder, CO.

 
Because diamond synthesis is constantly changing, certain tests you may have relied on in the past to distinguish synthetics from naturals may not be as reliable in the future. This recent spectroscopic analysis of the 1.16-ct. diamond shown at the top is one example. The 638 nanometer reading on the right side of the graph is seen in all synthetic diamonds tested so far, while the 701 nanometer reading on the left is the first known instance at this level. A test of similar material just a few weeks earlier found no such level. The test was made using the SAS2000 Spectrophotometer Analysis System, courtesy of Martin Haske, Adamas Gemological Laboratory, Brookline, MA.

"The problem in identification is there are so many ways to make synthetic diamonds," Grizenko says. "The different growth patterns and different colors associated with different methods can fool a lot of instruments." In addition, he says, producers are always tweaking their processes, which means a detection method that works one day may not work the next.

While processes to grow diamonds vary and change, processes to induce color in synthetic diamonds are often identical to the cause of color in natural diamonds. For example, traces of elements such as nitrogen are known to cause color in natural and synthetic diamonds. Irradiation and annealing (heating), or a combination of the two, also induce color in synthetics and naturals.

GIA has long studied the causes of color in treated diamonds. A report in the Fall 1998 issue of Gems & Gemology, for example, says irradiation with low-energy electrons and subsequent heat treatment changed one 0.09-ct. diamond from orangy yellow to reddish purple.

But again, Grizenko notes the processes used to grow gemstones are ever-changing and proprietary, so you can't use one set of guidelines to identify all synthetics. A spectroscopic reading taken on one synthetic diamond may differ from one for a comparable-looking synthetic diamond produced months later. "What's available today in 'black-box' detection equipment is hardly enough, particularly for colored diamonds, to detect everything, " says Grizenko.

Don't Panic
GIA scientists say retailers shouldn't panic. "Certain underlying principles in the make-up [of synthetic diamonds] do not vary," says Dr. Ilene Reinitz, one of the GIA-Gem Trade Laboratory's top scientists. "Between microscopic analysis and fluorescence, identification is straightforward." Reinitz, who is familiar with Grizenko's products, says she hasn't seen any synthetic diamonds that could not be identified readily.

Reinitz does say identification practices will have to become more rigorous. "Dealers and retailers should brush up on their identification skills," she says. To help, check the next column for a list of some common techniques to identify synthetic diamonds, as discussed in the 1995 Winter issue of Gems & Gemology. In addition, GIA offers a chart that lists the differences between synthetic and natural diamonds (call the GIA Bookstore at 800-421-8161). If you're still not sure, it's best to send the stone to a qualified laboratory for identification.

 Separating Synthetic & Natural Diamonds

Magnification

  • Natural inclusions, mostly transparent or translucent crystals of another mineral such as garnet, indicate the diamond is natural. Opaque inclusions warrant further study.
  • Opaque metallic inclusions indicate the diamond is synthetic. Hourglass shapes or cross patterns in the graining of a diamond are related to synthetics. Graining patterns are best observed under fluorescent lighting.

 

Fluorescence (Shortwave Ultraviolet)

  • Stones should be viewed in all directions in total darkness. Greenish fluorescence and hourglass or cross-shaped patterns strongly suggest synthetics. Heated synthetics often show strong yellow, orange and green fluorescence.

 

Spectroscopy

  • A 415 nanometer line is associated with natural diamonds. Lines between 500-700 nanometers are associated with synthetic yellow diamonds produced by the nickel-catalyst method. Red diamonds show a line at 638 nanometers. Caution: certain treated natural pink diamonds may show a line around 638nm also (see "Two Treated Color Synthetic Red Diamonds Seen in the Trade," Gems & Gemology, Fall 1993).

 

Magnetism

  • When you suspect metallic inclusions, use a strong magnet. If the diamond is attracted to the magnet, the stone is synthetic. If it isn't attracted to the magnet, however, that doesn't necessarily prove the diamond is natural. Further study is needed.

Excerpted from Gems & Gemology, Winter 1995

– by Robert Weldon, G.G.



Copyright © 1999 by Bond Communications.


 

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