When I first became a gemologist in the late 1970’s I appreciated emeralds. Very little treatment over the centuries. Just a bit of oil to seal the surface-reaching characteristics and brighten the stone. Then, came Opticon a resin filler that greatly improved the overall appearance and introduced otherwise cheap material thereby crashing the emerald market. It has since recovered a bit and resins are now the norm.
I then came to appreciate sapphires – usually heated but nothing more. Then came the diffusion process, then beryllium diffusion screwing up both the blue and fancy colored sapphire markets respectively. Sapphires may still be cool but untreated reigns supreme.
Ruby? While almost always heated, the process of using a crucible with flux leeches synthetic inclusions into their natural host – sometimes making them almost indistinguishable from a synthetic ruby. Yikes!
Now the prevalent ruby has a lead-glass in-fill that makes them truly a composite of ruby and glass. Transparent material that has a $2000/carat look sells for about a hundred. Lower end stones are a couple bucks a carat. The problem is many stores are selling this stuff without knowing what it really is.
Case in point. An NGL client walks in for a ruby appraisal. The ruby is glass-filled and valued at a small fraction of what his Internet seller has offered it at. He swears off the Internet and goes to a mall jeweler to buy a legit ruby. The jeweler confirms that they do not sell glass-filled rubies and obtains a stone from a respected source. Back to NGL for confirmation and guess what? SAME MATERIAL. LEAD-GLASS FILLED RUBY. The jeweler thought they were safe. The consumer thought they were safe. The reality was otherwise as a two thousand dollar ruby sale was reveled to be a sham. This a prevalent occurrence and one that usually goes unnoticed because the public rarely checks out their purchases and jewelers do not have the equipment or expertise to verify every vendor every time.
While this material, has been around a while, it seems to now be commonplace as not only cheap Burmese but African material has been so treated. So when buying a ruby, have your source specify what they are selling and offer an unconditional money-back guarantee if it proves to be otherwise or you are not happy. Important (expensive) rubies should be certified by the GIA, AGTA, AGL or Gübelin Lab for treatment disclosures. Many other “labs” (and a lot from Asia) just do not cut it, so a certificate may only be worth the paper it is printed on. An opinion of value is then placed by an independent lab (one not ready to sell you another stone) that you trust. Remember, an appraisal is an opinion of value by that appraiser and may not be reflective of what you are paying in your transaction. The colored stone market is not only complex for individual evaluations but extremely variable because of sale conditions and markets that can fluctuate from local economies or global market conditions. You should always buy based on what you like, not an appraised value, but you should also get what you were promised.
For more on identifying gems and their treatments take our Gemstone Identification I & II class, then follow up with Gem Evaluation for pricing information and join us at the world’s best classroom, the Tucson Gem and Mineral Show.
Just got a call that has me riled up – again.
It was from a “diamond dealer” (“I am selling diamonds on the Internet so I must be a diamond dealer”) who started railing on me for under-appraising a clarity-enhanced stone he had sold to an NGL client. Although I instantly recognized his lack of knowledge in the area, I allowed him to “school” me on why following how GIA grades diamonds was akin to following Adolf Hitler (no, I’m not kidding). I think the main reason for his rant was because my value determination was less than 20% his retail representation based upon the document of his “highly reputable” laboratory in New York. Never mind that by his own admission, my “low” value still exceeded his transaction price by 40%. He couldn’t understand why his lab’s “value” of seven times the purchase price was out of line!
Sadly this is a scenario I see repeated over and over again. If the seller would just represent their goods fairly and not promise the sky, they would not lose their sales when guys like me appraise them. Unfortunately, “guys like them” love to inflate both the “clarity” grade and value of clarity-enhanced diamonds. I used “ ” around clarity because the nature of this enhancement precludes the Gemological Institute of America (GIA) from issuing a grade. They simply identify the process and return the diamond, un-graded. But, since there is a viable market for this product, the industry is left open to “call ‘em as they see ‘em” by establishing “visual-only” equivalent grades. More on that in a minute. But first…
This process was developed by Zvi Yehuda and came to market in the mid 1980’s simply known as the Yehuda process. Kind of like a windshield repair, surface-reaching feathers are filled with a glass-like substance rendering them less visible. Many others now utilize this technology but Yehuda maintains the best-known brand name in this business.
*APPRAISER’S NOTE: The clarity-enhancement process is a treatment to fill surface-reaching fractures with a foreign substance to render those characteristics less visible. The apparent color may also be affected by this process. While historically stable under normal wear, this treatment is not stable under the conditions of jewelry repair work. Disclosure is required to anyone conducting repairs to the mounting or to subsequent buyers. The Gemological Institute of America (GIA) does not assign clarity grades to clarity-enhanced diamonds. This report provides a visual-only equivalent for insurance coverage.
The preceding statement is part of every CE diamond we appraise. Yes NGL appraises CE diamonds, but only for the consumer (not the dealers) and then using proper GIA standards in establishing what “visual-only” means. Even though the GIA will not recognize them for grading, a segment of the public likes the idea of buying a diamond “enhanced” through this process. The pricing is higher than the original clarity but less than the “visual only” grading.
So, this glass in-filling makes the diamond appear better but how do we grade it? The GIA says no grade but the public wants to buy it, so the appraiser has to establish parameters for an insurance appraisal. The general rules for clarity grading say to examine five factors of the characteristic inclusions and blemishes and how they appear at 10X magnification.
Those factors are the size, number, location, color and nature of the characteristics. There is no particular order of importance, but a give and take between what relevance each has with respect to an individual diamond. The “nature” factor has to do with what type of characteristic it is. A feather, which is a break in the diamond, i.e. fracture or cleavage is the most severe but if tiny in size has minimal impact. A crystal is not by its nature too detrimental but if dark and eye-visible is another story.
Since feathers are the principal characteristics being affected by the CE process the nature aspect is changed only by a lessened visibility. The feather itself is still there to its full extent. While warranting a higher visual-only grade, the type of inclusion has not gone away. The treatment is not permanent so its removal would immediately downgrade the look of the diamond. These facts cannot be ignored, but most labs pre-grading this material for the diamond brokers and manufacturers seem to not only disregard them but forget to use 10X magnification in the process altogether!
The caller I alluded to at the outset claimed that the GIA process of grading was not the only way and since the gates are wide open for interpretation on CE diamonds, I see what he means. I have examined numerous diamonds that had eye-visible feathers after treatment and still looked I-1 or I-2, only to be graded SI-1 and above on the accompanying “lab” reports. As a GIA Graduate Gemologist, I elect to follow the old school five factors guideline.
Funny that in pricing CE diamonds I am fair and consistent with the product sold so I must know its price. So, why must nearly every CE diamond get high-graded from the original labs and given stupid values only to get refuted when in the hands of a legitimate appraiser?
The issue is further exacerbated by non-disclosure many sales involve or the cryptic way the treatment is revealed. While the Yehuda folks and others have full disclosure, guarantees, etc. most of the sales we see come from second, third or fourth parties. We have addressed that before, so I won’t dwell on the issue. I merely want people to be reasonable in their representations, not hide behind bogus lab reports (which do not obfuscate the seller’s responsibility anyway) and make a fair profit selling something the public wants. Just like kids soccer – everyone wins!
To learn more about clarity-enhanced diamonds and how to identify them, take our Diamond Grading class where you will examine them as well as substitutes and synthetics.
The gemological community has recently been a buzz about the sale of so-called “hybrid diamonds” – a product we first encountered over five years ago but haven’t seen much of at NGL until just recently.
The stones recently received were identified as Cubic Zirconia (CZ), the most prevalent diamond substitute on the market, and available at less than a buck a carat. Our clients told us they had purchased synthetic diamonds – quite a different animal (mineral?) A true synthetic of diamond has the same basic chemical, physical and optical properties as a natural diamond (sounds like a definition, doesn’t it); it’s just grown in a laboratory. A CZ, or anything other than crystallized carbon does not qualify and is properly called a diamond substitute or imitation. The question then became, “Does this CZ have anything coating the surface?”
Let’s go back in time……
The first product we saw was marketed as an “amorphous diamond coating” over an undisclosed core stone. Since amorphous means non-crystalline, and diamond must be crystallized carbon, this is an obvious oxymoron regardless of what their supporting labs said. Being sold from our own backyard and documented by a local appraiser, we took interest and upon examination saw our old friend CZ. While the representative denied a CZ core, he finally relented and disclosed that yes, it was CZ, but with a proprietary overgrowth of diamond. If a coating was present it was beyond our methods of detection. We never really saw them for appraisal at the lab and I pretty much forgot of their existence other than the annoying fact that a local lab was providing paperwork and “graded” them with GIA standards as if they were a diamond. But, without a disgruntled client, I wasn’t about to “go after” anybody in this industry for just being misleading (I’d be up all night).
Now, with our disgruntled client list growing and the gemological community questioning the process and its disclosure, we are in the middle of it.
I have been to a lot of gemological conferences in the past few years and the coating of stones has lately been a hot topic – not from an identification standpoint, but from their prevalence in the marketplace with exotic names and innovative marketing. (Topaz is given a layer of metallic ions and ouilá Mystic Topaz!) In the past few months, however gemologists around the world have been discussing the “diamond coating” topic and I harkened back to the old days thinking “So, what’s new?” Well, it turns out it’s the number of companies marketing this or a very similar product.
So, I put on my forensic gemologist hat and took a look at some of the leading
websites to see how they described their products. If, as a Graduate Gemologist and jewelry appraiser of thirty years I was having trouble deciphering their lingo, what must the consumer think? A problem I saw was different marketing interpretations on what I later found out to be the same product. Different brands had different disclosures and words like “diamond hybrid” seemed most prevalent. If I read them right, technology has provided us with the breakthrough of an inexpensive diamond-like product free from conflict and environmental concerns. The talk shows love this kind of stuff. No support of terrorists. No exploitation of the environment or little kids in Botswana. Nice.
But, remember class, a name placed before or after “diamond” means it’s either a really famous diamond or a FAKE. So back to the question, is there anything on the surface and if so, what is it? I contacted a few of the manufacturers to enlighten myself.
The first thing I found out was many of the brand names come from the same lab. I also discovered that some of the manufacturers don’t like each other very much and claim the “other guy” doesn’t even create a coating. While the process may vary (and one may claim a different substrate, one a middle layer, etc) the overgrowth is basically a process that I’ve been talking to my students about for years – chemical vapor deposition (CVD). CVD diamond was developed in the mid 1950’s and can now produce full-grown gem quality synthetic diamond crystals when grown upon a diamond seed crystal. When grown onto another material it is not truly crystalline but polycrystalline – without geometric alignment. This may lead to a diamond-like resistance to scratching and if composed of carbon, you can see the effort to call it a diamond-like coating (DLC). But, since the process cannot yet produce crystalline diamond, it is not transparent and as the coating gets thicker, the surface clouds – not a good attribute for a diamond substitute. So in order to not loose transparency, the layer must be incredibly thin – possibly on the order of nanometers (one billion to a meter) if not angstroms (ten billion to a meter) making detection virtually impossible.
The fact that a diamond coating has not yet been detected by some of the world’s best gemological laboratories makes it hard to rate this product as being coated at all. NGL does not have the expensive equipment to do chemical analysis (donors welcome), but a colleague with the same equipment the sellers claim to have been used to “prove” the process, detected no surface treatment whatsoever. To take his testing further, (where no gemologist should ever go) he tried to scratch the surface with a number nine hardness point (sapphire) which would have no impact if the surface was diamond-like. In fact, he obliterated every surface. So, are the testing labs the manufacturers employ to justify their product just getting a better-treated specimens than the public or are they reading something into their findings?
As I speak, bigger brains than mine are looking into how to address this product, but I am willing to share some personal views.
For sake of argument, let’s take the manufacturers at their word and put their product to the identification test for synthetic diamond. By definition, a synthetic has the same, physical, optical and chemical characteristics of the natural.
Physically. Diamond’s big number is 10 – its hardness. Claims as high as 9.8 for the deposited material drop to a resultant coating of 9.1-9.3 and some direct testing of released samples were scratched by sapphire (9). Strike one.
Optically. It would be interesting to compare the refractive index, (R.I.) but alas, that measurement has not been made or cannot be performed (even though at least one website claimed diamond’s R.I. for their product). And, since if grown to measurable thickness it is not transparent, it would certainly not be gem diamond. We would call that bort. Strike two.
Chemically. Diamond is essentially carbon. Additional elements, like nitrogen if present are in trace amounts. The manufacturers own reports show a high degree of non-carbon elements present, like Yitrium. Diamond has no Yitrium! If this is the CZ substrate being recorded, that itself shows insignificant coating. Strike three. But then you’re out of this game with just one strike.
Conclusion. I don’t have a problem with the sale of coated CZ. I have a problem with the way this particular product is being marketed – confusing some and downright misleading others. If people want to spend $100-500 for seventy-five cent CZ with the hope of an improved look or durability, they may do so. This is America. However, the purpose of an enhancement is to improve an aspect of the product. This is a fundamental question here. The technology certainly exists to make what is claimed, but because of its very nature, has their been an improvement? And, since the claim of “diamond coated” is erroneous what terminology is acceptable? The public is very familiar with the term “diamond”. We are trying to teach them what a “synthetic diamond” is. The confusion level on this product is unfair to the consumer and needs to be addressed. The term diamond-like coating may be adopted but needs to be proven to the satisfaction of the gemological community. Then, an affordable test that confirms treatment must be available or the consumer has to take the seller’s word for it and appraisers won’t touch it.
This brings me to the other major point to be discussed. Is the gemological community and the public OK with labs that first accept the seller’s statements and then apply terminology as if grading a diamond? Color, clarity and “equivalent” diamond weight? The sellers love to take this information for price comparisons. “If this were a natural diamond it would cost…”
When confronted with this several years ago, I didn’t see enough to raise any issues. Since the certifying labs are in my own backyard, I also didn’t want the appearance of bashing a competitor. When asked if interested in being one of those labs I have always declined. Many respected gemologists just shake their heads over this practice, but remember there are few legal rules for evaluating gems and jewelry. In the gray areas for now, gemologists can practice however they wish.
With full and accurate disclosure I say buy it if you like it. “Because it’s not your mother’s CZ, it’s Diamondzilla – new and improved with DLC!”
– Learn more about these and other diamond substitutes in our Diamond Grading class –
As an example, at a chance escalator meeting, I introduced a few of my new students to Antoinette Matlins, an industry guru and author whom I attend conferences with. They were immediately treated to an impromptu gemological session as she launched into topics we had just discussed at our AGA conference the day before!
The educational opportunities alone make this trip worthwhile, as I have always advocated this to be the world’s best classroom for gemological education. You can learn about the pricing structure of colored stones by examining thousands of examples from live vendors. Actually buying at the best wholesale levels is just frosting on the cake.
If you are reading this and haven’t taken our gemstone classes, this is your opportunity to act on your passion. Take these two NGI classes – Gemstone Identification (usually offered three times a year) and Gemstone Evaluation (offered only once – in November) and you qualify for Ted’s Tucson Tour in February 2010. We will do a show preview in January and give you a two-day tour of the best gemstone venues when in Tucson. I will even negotiate with the dealers for you when you are ready to make that special purchase.
You will be exposed to industry giants and the most product – both loose gemstones (our forte) and finished jewelry at one gathering. Mineral, fossil and craft venues round out the best experience a budding gemologist, hobbyist or gem consumer could imagine. Start saving up.
Hope to see you there next year!
P.S. Did I mention the daytime temps were in the mid seventies and eighties?