The Diamond Alchemist ?
By Virginia Halevi - THURSDAY, JANUARY 15TH, 2004
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Changing the color of diamonds. Is it a process? Is it a treatment? Should it be considered a legitimate part of diamond manufacturing like irradiation, surface coating or fracture drilling? Or, should it be outlawed? Despised, reviled, thrown out of the industry into the murky world of the illegitimate. Just what does it mean to change the color of a diamond? What does HPHT really stand for? Should we care? Should the consumer? Will it destroy consumer confidence? Can it and will it harm the diamond industry? Or, at the moment, is there just a lot of talk and over-reaction about a process that, in one way or another, has been around since the mid-1940s?
Some of the answers we already know, but for most, only time will tell. What is certain though, is that 2004 is opening with a lot of confusion, concern and contradiction over what really is an HPHT diamond. The story of these chameleonic diamonds dates back some 60 years or so when the first commercial treatment for changing a diamond’s color began. It wasn’t the High-Pressure, High-Temperature (HPHT) process that is being used today, but it had the same effect - it improved the diamond’s color. This process though involved exposing the gems to radiation, which was somewhat of an unstable action. It did though break through some barriers. The industry at the time realized the potential of such a process and flags were waved. Horrified, trade leaders quickly gathered together to discuss what they assumed would be the devastating impending damage this could have on consumer confidence. At the same time, in the somewhat calmer atmosphere of the gem laboratories, researchers sat behind their microscopes and other gem paraphernalia to study the properties and traits of these treated stones. In fact, these radiated diamonds of the 40s gave rise to the GIA’s issuance of ‘origin of color’ reports.
Turning the clock forward half a century or so, the industry is still calling for urgent meetings to discuss color changing treatment on diamonds. The gem researchers are still locked behind their microscopes and equipment, examining and dissecting the properties of treated stones and consumers, are still, seemingly either unaware or uninterested in the whole story. In fact, it’s not only consumers, but many jewelry manufacturers and retailers are in the dark when it comes to shedding light on what an HPHT-treated diamond is. It is, after all, a natural diamond, so what makes this process different to any other manufacturing process? This is where all the controversy begins.
In the mid-nineties, Lazare Kaplan International (LKI) and General Electric (GE) submitted a number of diamonds to several gem labs for certification. No red flags were hoisted; the labs did their work and returned the diamonds with certifications. It was then that LKI/GE informed the labs that hey, these weren’t just any diamonds. These stones were some of the guinea pigs of a new technological process that they had developed - a process that improves the color and sometimes even the clarity of specific diamonds. According to LKI/GE there was no cause for concern, they urged the labs and the industry to accept this new process as merely an additional step in the traditional methods used in diamond polishing. In fact, when they first began the marketing of their treated stones they stated that the process ‘simply provides comparable conditions of heat and pressure allowing these crystals to spontaneously relieve themselves of their molecular street and return to the proper alignment and their original colorless state.’ It was, they said, purely ‘a process of restoration’, even coining the phrase that these HPHT diamonds were ‘The diamond nature intended’. Others in the industry took somewhat of a different view to this slant on the process. “No other process changes the physical properties of a diamond,” notes an executive of the World Federation of Diamond Bourses. (WFDB).
In late November 2003, representatives from the major gemological labs and industry organizations gathered at the New York Diamond Dealers Club to debate this thorny issue. While at present Lazare Kaplan’s/GE Bellataire line is the only official line of HPHT diamonds on the market, there has been an increase, especially over the past six months, of a greater number of treated diamonds on the market. Officially all HPHT diamonds when sold by dealers must be disclosed as having undergone treatment, but increasingly there are cases of HPHT diamonds submitted for grading without prior disclosure. It was the issue of how the gemological labs certify these, as well as prior disclosed HPHT diamonds, that would prove to be the overwhelming point of debate throughout the day’s talks.
Sitting around the large conference table on the 11th floor of the DDC, were representatives of most of the major gem labs, GIA, IGI, EGL, HRD and AGS, all of whom were in unanimous agreement about one thing, consumer confidence must be protected at any cost. Missing from the melee though was a presence from Lazare Kaplan/GE. It wasn’t that they’d boycotted the meeting, more that the meeting had boycotted them. Despite several phone calls to the DDC, Lazare Kaplan was very politely given the cold shoulder. “This is an industry meeting,” noted the conference’s coordinator, President of the DDC, Jacob Banda. “We are here to represent the interests of the whole diamond community, not just one particular company.” It’s a pity though that this one particular company wasn’t in attendance, after all who knows more about the process, disclosure and marketing of a treatment than the people who created it.
According to Tom Moses of the GIA, it was some six years ago, back in 1997, that the GIA first identified an HPHT stone. It wasn’t though by any means the first time a treated stone had been submitted for certification. At the time General Electric informed the GIA that it had some 1,000 grading reports from a variety of gem labs, which did not pick-up on the fact that the diamonds submitted had undergone this treatment. It was then that the flags were raised and the bugles played and the gem armies put on red alert. LKI/GE very quickly returned the 1,000 stones and their reports to the GIA to enable the GIA to further examine the stones. Eventually the stones were returned with a cert stating that they had been HPHT treated.
Since then the GIA has identified some 15,000 HPHT treated stones, which has allowed the lab to build a significant research database on the properties and characteristics of a stone that has undergone this color altering treatment. But, on top of the 15,000 there are a percentage of stones that leave the lab with a certificate that states the stone is ‘undetermined’. ‘Undetermined’ is the euphemism used for stones that according to the lab’s examination might or may not have been HPHT treated. For the owners of such stones this is not a satisfactory result. If a dealer has bought a stone that is a ‘natural’ untreated stone, yet shares certain physical traits in common with treated stones, their diamond is tainted with a question mark. Some labs will even hold a stone for up to six months in a quest to fully determine whether it is or isn’t HPHT. Unfortunately though a final answer isn’t always forthcoming. “We don’t foresee a situation at present, in which we will be able to identify 100% of HPHT diamonds,” warned Moses.
On the other hand the HRD laboratory is ‘quite confident on their detection of HPHT stones’. “But,” continued HRD’s Peter Borgmans, “there remains a small percentage of stones which we flag as undetermined.” The IGI are even more certain, actually they state they have ‘absolute confidence that all colorless diamonds, which have been HPHT treated are detected when submitted to the IGI for grading’. Turning to another lab, the AGS, they are more in line with the opinion of the GIA. There are cases, they say, where they simply cannot be 100 percent positive if the stone has been treated or not. Unlike the GIA, the AGS simply returns the diamond with a certificate stating the stone is a Type Ia or Type IIa. “This raises a flag for the client,” explains AGS’ Peter Yantzer. “They are now aware that the stone is of the type possible for HPHT treatment.”
So, we know what the labs do when they suspect a stone has undergone the treatment but, to calm nerves and protect consumer confidence, is this enough? Most definitely not,” emphatically states WFDB’s Meir Wertheim. “Dealers are worried that a sizeable portion of HPHT treated diamond escape detection. Not all the gem labs have the equipment to detect the process. On top of this, each lab operates independently and at present there are no uniform regulations implemented by all labs.”
Over in the U.K., there is another army - these are the soldiers of the Gem Defensive Battalion, with their base in the De Beer’s research center in Maidenhead, England. These gem defenders have been working for several years on the development of relatively inexpensive, quick and easy to use screening instruments. In 1996, they came up with the DiamondSureTM and then the DiamondSure 2 - machines that not only separate natural from synthetic diamond, but also explicitly identifies Type II diamonds. At the end of the month, De Beers announced that it would make such technology available to organizations that requested it.
And so it came time to really address the issues relating to HPHT. The process is here to stay. However much some would like the treatment to be outlawed, the machines thrown into a garbage dump and HPHT to disappear from the diamond industry forever, that isn’t going to happen. Only now, are some waking up to the fact that it’s time to deal with issue, implement regulations and enforce transparency. For this, there needs to be unanimous consensus throughout the industry organizations and gemological laboratories
First off, all in New York agreed after several hours of debate that gemological labs must have some form of nomenclature on a lab’s report over what precisely is HPHT. Some referred to HPHT on their certificates as a stone that has undergone HPHT treatment to ‘improve’ its color. Others describe the process as ‘altering’ the color of a stone. ‘Improved’ or ‘enhanced’ were considered to be too ambiguous, with terminology such as ‘modified’ ‘altered’ or ‘changed’ preferred as describing the effect the process has on the color (and in some cases clarity) of the diamond. “If each lab describes HPHT differently, how can a consumer understand what HPHT is?” asked Mark Gershburg of EGL.
But, it will take a bit more than wording to help ensure full disclosure of all HPHT stones being traded on the market. At present, all the labs, bar the AGS, will only certify a HPHT stone (disclosed as such on their grading certificate) if the stone is laser-inscribed on the girdle as HPHT. If, they say, the client refuses the lab permission to laser-inscribe the stone, then they return the diamond without certification. However, for many present at the meeting this was not guarantee enough.
One participant even called for the labs to hold all HPHT stones if the owners do not agree for the diamond to be laser-inscribed on the girdle as HPHT. The labs and other delegates quickly shot down this idea, but it just highlights how concerned many in the diamond industry are over the impact that non-disclosed HPHT diamonds may have on consumer confidence. “The GIA offers full disclosure, but it does not pass judgment on a product and a process,” rebutted Moses. Agreeing with this take Jerry Ehrenwald from IGI noted, “labs aren’t police and as yet there is no law regarding obligatory laser-inscription on HPHT treated stones.”
However, the WFDB stepped in and agreed to issue a recommendation that all HPHT stones that are graded by laboratories will be laser-inscribed HPHT. This sounds good in practice, but in reality, can a lab inscribe a diamond without the owner’s permission, or even contrary to the owner’s permission. Does this mean then that the diamond will be returned without a certificate and without laser-inscription? And, will all labs, not just the ones present in New York agree to this?
So, we know stones that undergo HPHT have to be Type Ia or IIa diamonds and, more often than not, the clarity of the stone has to be VS or above. Stones of a lower clarity are highly susceptible to breakage during the process. “If the clarity is not high, it is reasonable to assume the stone won’t have been HPHT’d,” explains Moses. But, once again as technology improves, so does its capabilities. Moses followed on this statement noting that the GIA has recently seen an increase in lower clarity diamonds that have been HPHT treated. In fact, the type and number of diamonds being treated is expanding, smaller sizes and lower clarities and subsets of colorless can also be targeted as suitable for HPHT. According to the HRD, some 10 carater pluses are now being HPHT treated.
There have also been instances in which HPHT treated stones undergo a secondary treatment to hide that fact that they are HPHT. According to the HRD who reported this alarming trend, such deception isn’t working, with the lab saying that they still detect the stone, just that it is harder to make a 100% determination that that stone is HPHT. “But,” insists Borgman, “such stones are flagged as questionable. They don’t escaped detection.” But, how can we really know what percentage of HPHT diamonds escapes detection? At the moment, we can’t.
What is a Type Ia diamond or Type IIa? Type I diamond account for some 95% of the world’s diamond production. A Type Ia (a subject of Type I) is a stone in which nitrogen atoms are present in pairs or groups. Type IIa are very rare, they account for only 2 percent of the global diamond supply
Type IIa classification is given to diamonds that are chemically very pure - containing nearly undetectable amounts of nitrogen. Type IIa are usually brown in color, but occasionally they are produced as colorless. If they contain boron then they will appear with a blue to gray hue.
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Recently, Bellataire Diamonds submitted one blue and two pink high pressure/high temperature (HPHT) processed diamonds to the GIA Gem Trade Laboratory. Matthew Hall and Tom Moses of the East Coast Gem Trade Lab provide this brief follow-up to the Fall 2000 G&G Lab Note on pink and blue HPHT-processed diamonds.
The 7.54 ct pear shape (see photo) and the 4.57 ct emerald cut had colors equivalent to Fancy purplish pink and Fancy Deep brownish pink, respectively. The 0.73 ct marquise cut was equivalent to Intense blue. The gemological properties (color zoning, reaction to UV radiation, etc.) of these diamonds overlapped those of their natural-color counterparts. Both pink diamonds were type IIa (i.e., they contained a nominal amount of nitrogen), and the blue diamond was type IIb (i.e., it exhibited boron-related absorption peaks in the infrared, and was electrically conductive). However, close examination of the 7.54 ct pear shape revealed an etched and pitted surface on a pavilion facet, which was probably the result of the high temperature procedure used to enhance its color.
Low-temperature photoluminescence (PL) spectra were obtained from each of these diamonds with a Raman microspectrometer. On the basis of our own criteria and data from the literature, we were able to differentiate the spectra of these diamonds from those in our collection of more than 800 low-temperature PL spectra of natural-color pink and blue diamonds. These results further confirmed the usefulness of low-temperature photoluminescence in the identification of color-enhanced diamonds
