Diamond Substitutes - What is the Real Deal?

What word bonds all the following adjectives?

Treated
Substitute
Synthetic
Simulant
Enhanced

Give Up? ... Diamonds. But what really is a treated diamond, a man-made diamond or a diamond simulant and just how easy can they be detected? A diamantaire's greatest nightmare is unwittingly buying a diamond simulant, "I simply don't know enough about all the new treatments, substitutes and new materials out there," A prominent expert sheepishly admitted recently, and he's not alone. While most diamond treatments, enhancements and substitutes are quite easily identifiable to the trained eye (and many of those that are not, can be distinguished in a rudimentary gemological laboratory), there are some that are still cause for concern. Detecting such treatments and materials is difficult, based sometimes on little more than suspicion and a gut feeling. There are even rare cases in which unscrupulous dealers have purposely erased laser marking or other such engravings that identify the stone has having undergone such treatment. Jewelry.com takes a look at the various treatments and substitutes on the market and finds out exactly how easy it is to identify them and if not, what are the tell-tale signs to look out for.

Moissanite

As was reported in our story Is it Diamond, or is it Moissanite? a few years ago this diamond imitation was introduced into the market causing waves of panic among concerned dealers. How could they identify it? What would be the impact on consumer confidence? What would this new gems presence and affordability do to the established diamond market? Moissanite was not though a newly discovered diamond substitute. The first Moissanite stones were discovered in 1893 by a French chemist named Henri Moissan while investigating a meteorite that had landed in Diablo Canyon. After conducting research on the stone, he concluded that the mineral was made of silicon carbide.

For over a hundred years the stone was little more than a footnote in research books. Then, in 1995, Cree Inc. a US based company that manufactures silicon carbide devices, developed a synthetic Moissanite from silicon carbide crystals.

Naturally occurring Moissanite, from which the jewels are made, is dark green or black, found in very limited quantities and is not commercially viable. Cree discovered a process of taking the minerals silicon and carbon, evaporating them into one compound, then growing them into a crystal. This crystal is cut into the final Moissanite jewel, either nearly colorless, like a diamond, or in various shades of green. In 1995, one of the principals involved with Cree founded a company, C3, which was to be later renamed Charles and Colvard. It was this company that for three years developed the process of creating synthetic Moissanite and the following manufacturing of the stones, before hitting the consumer market with the latest "diamond substitute" in 1998. During that first year, Charles and Colvard recorded Moissanite sales of some $4 million. This more than tripled in the second year to over $12.2 million in 1999, continuing to increase in 2000 to stand at $12.7 million. Moissanite though hasn't been exempt from the drop in jewelry sales in 2001, as sales tumbled by a quarter.

Near colorless Moissanite has very similar physical properties to those of diamond; for example, Moissanite tests positive for diamond on conventional thermal probes. Almost all diamond simulants share one property with diamonds: they are singly refractive. A ray of light passing through the gem is slowed but otherwise unaffected by the medium. Synthetic Moissanite is doubly refractive. This means that a ray of light passing through the stone is slowed, bent and split in two as it passes through it.

To the average eye Moissanite seems virtually as beautiful as a diamond, though its color is lower. At first sight, both inside and on the surface, Moissanite' s brilliance seems to be softer and cloudier. The sharp effects of the color spectrum in a regular diamond are enticing and the human eye easily registers the stone's distinct nuances. On the other hand the color spectrum effects in Moissanite are more spread out. On the hardness scale, Moissanite is only slightly softer than diamond, registering 9+ on the Moh's scale, as opposed to a diamond's 10.

Moissanite, along with other synthetic and treated stones now account for about US$500 million out of the U.S$22 billion diamond jewelry market. Moissanite for example costs about one-tenth of its diamond counterpart. A one-carat Moissanite stone set in 14-karat gold would retail for somewhere around the $700 market, compared to a one-carat diamond in an identical setting, which, depending on the quality of the stone, would retail from $4,500 to $6,000. Mercifully for the diamond market, since the first introduction of the stone to consumers, marketing of the stone has been focused away from promoting it as a diamond imitation, rather as a gem in its own right. In fact many of the stores and online sites selling Moissanite jewelry don't even mention diamond or diamond substitute.

Man-Made Diamonds

A bigger challenge facing the diamond detectives is the detection of synthetic diamond. Natural diamond is formed at extremely high temperatures and pressure, at a depth of some 200 kilometers under the earth's surface. Technological innovations now mean that these conditions can be almost exactly recreated in a laboratory environment. A Synthetic diamond, as opposed to diamond substitute, according to its creators, ‘is a real diamond' created above ground in a fraction of the time compared to its ‘below' ground counterparts.

In 1999, a Florida based company, Gemesis (you read that right), enlisted help from scientists and engineers from Russia and the University of Florida produce man-made gem quality diamonds using a small high-pressure, high temperature machine. Within the first year, the team created some 230 yellow, amber, green and colorless diamonds, with the machines producing a one carater in just under 50 hours. About twice the size of a domestic washing machine, the device utilizes a carbon source and a shard of a real diamond (a seed), squeezing the "seed" with increasingly high pressure topping out at some 850,000 pounds per square inch. Other equipment then heats the core to up to 3,000 degrees Fahrenheit. The high pressure combined with the rocketing temperatures combine to transform the shard of diamond into a much larger stone.

Three years on and Gemesis (you read that right) is now producing ‘The Gemesis Cultured Diamond™' up to 2-2.5 carats, in yellow, intense yellow, orange, yellow-orange, VVS to SI, in round brilliant, radiant and princess cuts. The company is even scheduled to open a $25 million manufacturing plant in mid-2003 that could house some 300 of the diamond producing machines capable of producing 30-40,000 stones annually. While most of the production has so far been in yellows, the company is now hoping to come up with blue, pink and colorless stones. If production of such scale does take place, two major issues are of paramount concern. At the moment the company vehemently stresses that it will take all precautions to ensure that the The Gemesis Cultured Diamond™ "is on the level", i.e. even laser inscribing each diamond as such. But, as experience has proven, unscrupulous people could (and in the past certainly have) erase such inscriptions in an attempt to deceive both the gemological laboratories and unsuspecting consumers. Especially when the price of a lab-grown diamond is about half of it's naturally produced counterpart. If this were to occur, damage to consumer confidence in diamonds would seriously suffer. "The World Federation of Diamond Bourses (WFDB) should include the regulation of laboratory grown diamonds within the scope of their activities," urges Udi Harel, the Israeli representative of Gemesis, "the industry needs to know what is a synthetic diamond. At the moment many people confuse a synthetic with a simulant, they are entirely different. Manufacturers and dealers need to be get up to date and fully informed with what is out there on the market." Currently Gemesis issues a ‘Certificate of Authenticity and Quality' with every stone. The company, or its' representatives, ensure that every buyer signs a document stating that the stone they purchase is a laboratory grown diamond, and throughout any transactions forward, full disclosure to the buyers must be forthcoming. This, though, is all voluntary. No body at present regulates disclosure; the polished output need not even bear any laser inscription indicating that it is a man-made diamond.

There remains much concern whether the machine-made diamonds could be distinguished from a natural diamond, as the only difference between the stones could be recorded at the atomic level; natural diamonds having paired nitrogen impurity atoms while Gemesis's man- made stones hold single atoms. At present, most of the synthetic diamonds on the market have an intense yellow to orange-brown color, rendering them easily detectable, but the identification of nearly colorless synthetic diamonds, (if and when they hit the market) poses much more of a problem.

Some source material reprinted with permission from IDEX Magazine.