Diamond Substitutes - What is the Real Deal? Pt. 2

Treated Diamonds
In part 2 of our series on Diamond Substitutes and the fears consumers have over being "hoodwinked" on their gem purchases, Jewelry.com continues to inform our members regarding diamond treatments and enhancements. Our report identifies some of the treatments, points up industry and consumer concerns and tells of the measures being taken in the industry to detect, track and register all such enhancements and maintain strict control of them in the marketplace. The most recent of which and causing the most concern regarding "Enhancement Detection" in the diamond trade is a new process developed by, of all organizations, General Electric.

High Pressure, High Temperature (HPHT) Treatment
In 1991, a subsidiary of Lazare Kaplan International, Pegasus Overseas Limited - later Bellataire Diamonds - announced a new technological process developed by General Electric scientists to improve the color and other characteristics of certain natural diamonds. GE revealed to the Gemological Institute of America that the process entails the stone being subjected to high-pressure, high temperature (HPHT) conditions. Prior to the public announcement regarding the treated diamonds, Bellataire had submitted a number of processed diamonds to several laboratories, including the GIA Gem Trading Laboratory, for grading reports. The grading reports made no mention that any of these processed diamonds appeared unusual in any way. In various statements, GE and the Bellataire representatives maintained that the results of the process were "permanent and irreversible," and that it did not involve any conventional diamond treatments such as irradiation, laser drilling, surface coating or fracture drilling. The new process was merely an additional step to the traditional methods used to transform rough into polished diamonds. Bellataire further noted, the process should be considered as part of the normal manufacturing of diamonds; saying in their marketing materials, "The GE Process simply provides comparable conditions of heat and pressure, allowing these crystals to spontaneously relieve themselves of their molecular street and return to their proper alignment and their original colorless state." It is this process of restoration that leads Bellataire to describe there stones as ‘The Diamond Nature Intended.'

What exactly is a Bellataire diamond? The diamond itself is Type IIa, which accounts for only 1 percent of the world's rough diamond production. Type IIa stones are brown in color and generally considered nitrogen free, though this is not entirely accurate. The stones actually contain nitrogen, albeit in microscopic amounts. Researches at the Gubelin Gem Laboratory in Switzerland believe it's this minuscule quantity of nitrogen that once reconfigured by the GE HPHT procedure enables the brown diamonds to become white.

Bellataire diamonds cover a wide range of color grades, but the majority are "colorless" or "near colorless" (from grades D through G). In an exceptionally savvy and prudent move, the company decided to market the stones directly to the end consumer, not to wholesalers or dealers, thus reducing the risk of erasure of the laser-inscription and serial number identifying the stone as undergoing the HPHT process. The publicity generated throughout the media when the process was first publicly launch garnered a huge amount of negative feedback from the industry. Fears of an almost catalytic destruction in consumer confidence, a market flooded by the treated stones, with no sure-fire method of detection available, failed to materialize. In reality, the deluge of coverage enabled the company to introduce the stones onto the market in an effective way, "there was hardly a person in the industry who didn't know what an HPHT diamond was," recalls one of the scientists involved in the project.

In contrast to diamonds that have undergone the traditional enhancement treatments, Bellataire stones are sold as high-end luxury products. The stones are available in D-H color, VS upwards, with premium cutting. As the IIa stones constitute just 1% of rough output, the market for the stones is quite severely restricted with the company placing a cap on approximately 40-50 retailers that will carry the Bellataire jewelry line. When first launched, Bellataire estimated sales topping $100 million a year, but this overly optimistic estimate was quickly revised with sales now projected to top at about $30-$40 million a year.

Treated or not, consumers are buying the stones, as one retailer noted, "once they understand the treatment is permanent, customers love the idea that the diamond they are buying is somewhat different."

Concerns Over HPHT
There are fears at the moment regarding the GE HPHT diamonds and the lack of technology available to detect such treated stones. According to Mazal U'Bracha of the De Beers' Gem Defensive team in Maidenhead, England, The initial GE-LKI announcement regarding HPHT treatment caused significant concern because of the implication that such stones were indistinguishable from similar untreated diamonds. These initial concerns were addressed via the introduction of laser inscriptions on the girdles of GE HPHT treated stones allowing them to be readily identified as such and certification stating that they had undergone the GE process. This disclosure is continuing.

Mr. U'Bracha went on to explain that, the real concern in the trade is regarding possible undisclosed HPHT treated stones and the need to detect them. Considerable progress has been made regarding detection since the emergence of HPHT treatment as a significant gem threat, with new and more-sensitive techniques being applied to the problem. Suitably equipped laboratories are now able to detect the vast majority of HPHT treated diamonds. The situation is complicated by the fact that the starting material is a natural and not man-made product and therefore varies considerably in its properties. Color improvement of varying degrees can be induced by subjecting the diamond to a wide range of treatment conditions that will result in very different spectroscopic characteristics. It must be remembered that GE is not the only company treating diamonds and that the stones produced by different treaters will vary in their characteristics depending on the starting material available to them and the treatment conditions they apply.

The situation is constantly evolving and the criteria used for identification are under constant review. Research in this area is actively seeking to extend detection capabilities. Laboratories worldwide have invested heavily in the equipment needed to handle detection and this is complemented by the investment made in skilled staff that has the necessary knowledge to interpret the available data.

Scientists at DTC Research Center (The DTC Gem Defensive Program is a collaborative effort involving the DTC Research Centre, focused on gem diamond research; the Diamond Research Laboratory in Johannesburg, South Africa) have made a substantial contribution to research in this area and continue to liaise closely with the major laboratories involved in discrimination of HPHT treated diamonds. In addition they seek to assist gem-testing laboratories by developing practical instruments to deal with complex identification problems. To this end, a low-cost, easy to use instrument, currently in prototype form, is being developed for rapid screening of potentially HPHT treated type II diamonds. This instrument will not replace the sophisticated laboratory equipment but it will greatly reduce the number of stones that will need to be examined in such a time-consuming way.

Treated Colored Diamonds (Blues and Pinks) vs. Colorless
The type of diamonds that are treated to produce pinks, blues and colorless stones have very low impurity contents so require advanced spectroscopic techniques to discriminate between HPHT treated and natural untreated stones. Criteria do exist for the identification of HPHT treated stones belonging to all the above types (colorless, pink and blue) and successful identification is possible in the vast majority of cases. In a small number of cases identification is subtle and investigations aimed at strengthening and extending current criteria forms a significant part of the on-going research Program at DTC. What is the situation with type Ia yellow browns in which the HPHT processing turns them into fancy yellowish green and greenish yellow colors. Is there technology to detect the treated stones?

Type IA diamonds contain significant concentrations of nitrogen impurity and specific forms of nitrogen related defects are responsible for the final color in HPHT treated type Ia diamonds. The presence of readily detectable amounts of nitrogen-related defects provides a number of spectroscopic features that allow identification of such HPHT treated stones. Many of these features can be observed using relatively simple absorption spectroscopy, a technique available to a significant proportion of gemological laboratories. As for type IIa stones, there is considerable variation in the starting material and this can potentially generate stones with unusual characteristics. Research is continuing to refine and improve existing HPHT discrimination criteria.

Laser Drilling and Fracture Filling
Laser drilling and fracture filling are the two most common methods of disguising inclusions in diamonds. Laser drilling is used to lighten visible inclusions in the stone. With the aid of a laser, a beam cuts into the inclusions and black carbon material is removed from the drill hole. A bleaching chemical is then fed into the opening to change the inclusion from dark to light.

This process ultimately improves the clarity of the stone. The process is generally undertaken in lower quality stones with clarity grades ranging from 6 to 9.

Until recently, the Federal Trade Commission (FTC) guide did not mandate the disclosure of laser drilling in diamonds. On December 1, 2000, the FTC responded to a November 1998 Jewelers Vigilance Committee (JVC) petition to revise the guide. As a result any treatment to gemstones that significantly affects the value of the stone, including laser drilling in diamonds, must be disclosed.

Another, somewhat controversial treatment is ‘fracture filling'. This technique is used for diamonds with feathers that are highly reflective and visible. The process requires that the feather must open to the surface of the stone. In a vacuum environment, the air is removed from the inclusion and is replaced with a substance that has a high refractive index and a low melting point. The replacement substance contains elements such as lead, bismuth and bromine. Since the optical properties are similar to the diamond, the filling - and the feather - are minimized. But, the presence of the materials can be detected with X-ray fluorescence techniques. In fact, it is even possible to distinguish between the filling materials used by different firms supplying the crack filling. Crack fillings must always be explicitly disclosed.

Fracture-filled diamonds though must be treated with kid gloves. Any deviation from the special care instructions and the filler can evaporate or change color. GIA, for example, will grade diamonds, which have laser drill holes (with an appropriate note on the report), but will not grade stones which has been filled with a foreign substance.

Irradiation
The first method for improving the color of a stone was developed over a hundred years ago. In 1904, Sir William Crooks began to irradiate diamonds by submerging the stone in radium bromide for several months as the surface of the stone was bombarded with energetic particles emitted by the radioactive atoms. This treatment though was soon abandoned as the realization hit home that wearing a radioactive diamond was not a healthy choice.

Irradiation still takes place with diamond colored by fast neutrons in a nuclear reactor. After irradiation, the diamond has a green or blue-green color. The stones are then annealed or heated to soften the shade back to a desirable and permanent color. Such a treatment must be disclosed.

FTC Regulations
Although laser drilling is a permanent treatment, the new regulations require sellers to disclose the use of lasering based on the JVC's petition that a laser-drilled stone is worth less than comparable non-drilled diamonds. In the revised section of the Federal Trade Commission Guide it reads: ‘It is unfair or deception to fail to disclose that a gemstone has been treated if:

The treatment is not permanent. The seller should disclose that the gemstone has been treated and that the treatment is or may not be permanent;
The treatment creates special care requirements for the gemstone. The seller should disclose that the gemstone has been treated and has special care requirements. It is also recommended that the seller disclose the special care requirements to the purchaser;
The treatment has a significant effect on the stone's value. The seller should disclose that the gemstone has been treated.

What treatments/synthetics/substitutes are causes for concern at the moment due to lack of detection methods with present-day technology?

According to the DTC, there should be no issues of major concern with respect to detection of synthetic diamond, simulants or clarity enhancements. All gemological laboratories should be in a position to effectively and rapidly detect these materials and treatments. Detection of HPHT treated natural diamond does present unique identification challenges, in terms of the technology and expertise required to effectively detect such treatments. It is encouraging that laboratories worldwide have invested in the equipment and skills required to handle detection of such diamonds.

Have there been cases of non-disclosure vis-à-vis treated stones that have had their laser inscription removed?

There were initially few reports in the trade press regarding the removal of laser inscriptions and we are not aware of any recent reports. Disclosure is a very important component in the task of maintaining confidence in the integrity of natural untreated diamond and DTC fully supports moves to provide the consumer with the simple identification means afforded by laser inscription.

The possibility of fraud means that disclosure must be supported by a robust means of discrimination. In the case of HPHT treated diamonds this can only reliably be provided by detailed spectroscopic examination by a fully equipped gemological laboratory.

Some source material reprinted with permission from IDEX Magazine.