Hey Loungers,
We have all heard about a number of gemological labs and all assume that gemological reports, being commonly miscalled gemological certificates, are the alpha and omega of gem buying.
Well, here’s the thing, while it is indeed a necessity to have a gemological report on the gemstones you purchase, they are in no way a guarantee that what’s written in them is indeed 100% accurate. This is why, on occasion, gemstones come with two or three different reports that may or may not say the same thing when it comes to origin or treatment.
As some of you might already know we, at AsiaLounges, tend to use the services of Lotus Gemology to know whether our stones are indeed what we purchased and therefore, what we eventually provide you with.
Lotus Gemology is known for being one tough cookie on treatment detection which is one of the main reasons we use their services. Of course, the fact that their reports are super slick does not hurt either!
Three of the five gemologists they have in house are nothing short of legendary and, we have the pleasure of discussing once more with Billie Hughes about a topic that is, strangely enough, seldom addressed: instruments, how they are used and or why.
Today, with Billie we are going to investigate the reason why modern instrumentation is important and why, it may or may not suffice to cast a proper judgement call on a stone origin and treatment!
Without any further delay, we propose you to discover what Billie has to say about her tools, how they are used and whether or not having all the latest cool toys is enough to run a lab or if there’s more to lab gemology than running fancy gears!
Billie, the floor is yours,
AsiaLounges: Hello Billie, thanks for coming back for round three or four here for A Gem Dealer’s Journal. I know we’ve gone through that before but, could you tell us briefly more about you, your team and your lab as an introduction?
Billie Hughes: Thanks for having me back, Simon.
I am a gemologist at Lotus Gemology, which is a gem testing laboratory based in Bangkok, Thailand. Our lab specializes only in testing colored gemstones, rather than diamonds. We are particularly known for our experience in working with corundum (ruby and sapphire). We are also a family-owned business which my parents, Richard Hughes and Wimon Manorotkul, and I founded together in 2014.
In addition to testing clients’ stones and issuing reports, we also do a lot of research which we share in our books, articles, and lectures.
Personally, I have found a particular interest in gemology that I like to focus on, which is photomicrography. This means taking pictures of the inclusions, or features, that I see within gems while using the microscope.
My work in the lab has been a fascinating journey. Lotus Gemology is a small business, and that has given me a wonderful and varied set of experiences. As a young gemologist it is great to have the ability to do so much. I have the opportunity to run each piece of equipment, to test stones in the microscope, to indulge in my hobby of photomicrography, to do field gemology and research. But what’s a little unusual is that I’ve also had the opportunity to interact a lot with clients, and it has given me an appreciation that sometimes there is a disconnect between how labs and our clients, the dealers, understand gemology. In fact I think discussing this point is how you and I started brainstorming the idea for this conversation.
AsiaLounges: In order to give a tid bit of context to our readers prior to getting into discussing the gears, could you please tell us, quickly what are the possible testing paths that a stone takes when entering one of your take-in windows? Are there different tests that one runs whether a stone is treated or not? Would all stones be measured or would all stone end up in an immersion cell and why?
Billie Hughes: As we get into our discussion of lab testing, I should mention that we will be discussing generalities of testing that apply to most stones. Of course when we are dealing with natural materials like gemstones, each piece is unique so there will always be exceptions to the rules.
Every stone that comes into the lab is taken through a series of tests. The gemologists that are testing the stone will look at the results indicated by all of this data before drawing a conclusion about the final identity, enhancements, and origin of a stone. While each stone goes through a variety of tests, it is not always necessary or possible to run every test on every stone. There is no single test that tells us everything we need to know about a stone; we need to look at the complete picture of a piece.
When a client drops a stone off for testing, we immediately weigh it if possible. Each stone gets separately bagged and is assigned a number that allows us to track it through our system. We also ask for a declaration of the type of gem being submitted, whether it has been enhanced, and what the origin is if known. Some clients are surprised to hear that we ask for these declarations, and we are often asked why we request this information. There are a few reasons why we ask for this information.
-
One is that it helps us process stones more efficiently.
-
Another reason is that if there are any new developments in the market, such as a find in a new locality, we would like to hear about it.
-
I also think this is a great opportunity to discuss any reservations the client may have about a stone. Some clients submit stones that already have multiple, conflicting reports, and often have questions we can address.
Once a specimen comes in for testing, it is weighed and measured.
Then there are some test we routinely run on all stones of each type. Some tests, like obtaining the UV-Vis-NIR (UV Visible Near Infrared) spectrum are run on almost all stones. Other tests may depend more on the stone type. For example, the Raman spectrum can help us identify many types of gems. In the case of spinel, it can even help us separate natural, untreated spinel from heated and/or synthetic spinel. Because of this, we routinely test spinels with the Raman. However for corundum (ruby and sapphire), a different instrument, the FTIR, generates spectra that can provide indications of whether the stone has been heated. Thus, we routinely test corundum with the FTIR.
In addition to running certain spectra, our gemologists will examine each stone. We will decide on how the color will be described on the report, run basic gemological tests like the polariscope or spectroscope, and look at spectra that have been collected. The most important step is the microscope.
We examine each stone in the microscope to look at the inclusions, which can tell us so much about a stone’s identity, treatments, and where it might be from. After this observation, in some cases, the gemologist may decide to summarize the results in a final ID. In other cases, depending on what we’ve seen, we may decide further testing is needed.
For example, if a ruby or sapphire has been heat treated at high temperature, it may need further testing for beryllium. If we see interesting solid inclusions, we may want to take the specimen over to our micro Raman station to identify the inclusions with Raman spectroscopy. A stone that has fissures may need to be checked for filler, whereas a stone without fissures will not have filler.
Another step is that each stone will be photographed so that a photo can appear on the report to help identify the stone. On request, some of our clients also ask for additional photography. They may ask for an additional profile shot with a background, which we call a “Bespoke Photo,” and some clients also ask for an inclusion photo. This provides a unique identifying marker for the stone.
As a part of our process, stones will not be tested by just one gemologist. We always have at least two gemologists look at each stone to check each other’s work.
To answer your question about the immersion cell, not all stones would be put in an immersion cell. However, an immersion cell can be a valuable tool in certain cases. For very clean stones, immersion can sometimes help us better see growth features, which can help us distinguish between some natural and synthetic stones. In other cases, it can also help us see that a stone has been diffused, for example with Be (beryllium) or Ti (titanium). A gemologist will decide when this test is necessary.
To summarize the basic process, a client submits the stone to the lab. The stone will be weighed and measured. Then basic spectra will be run (this could include UV-Vis-NIR, Raman, FTIR, and UV Fluorescence spectroscopy). Then gemologists will examine the stone and do both basic gemological tests (such as the polariscope, taking an RI, etc) and take a look at the spectra that were run in the previous step. They will also examine the stone under the microscope, and then decide if a final conclusion can be drawn, or if the stone needs further testing such as a fade test, a check for beryllium, or another test. Once any further testing is done, a final conclusion will be drawn (by at least two gemologists). A photograph of the stone will also need to be taken for the report. Once all the necessary steps are completed, a report can be printed.
AsiaLounges: Let’s start by the standard items that one may see in virtually every and all labs as well as being the first tools that one would learn how to use as they go through gemology classes. Can you tell us more about the microscope, polariscope, spectroscope and why they are used?
Billie Hughes: The microscope is the most important and versatile tool in our arsenal. Using the microscope allows us to examine stones at high magnification, and there is so much we can learn. We can often find clues about a stone’s identity, origin, or if it has been treated by using microscopy. However, it’s also an interesting tool because unlike the others that we find in the lab, it doesn’t give us any kind of quantitative data. There’s no reading or spectrum here; the use of this powerful instrument depends on the skill, experience, and patience of the gemologist.
Microscopy is used in conjunction with the other tests, and these methods complement each other. For example, I may look at the UV-Vis-NIR spectrum of a stone and determine that it is a ruby. However, when I examine the stone in the microscope, I might see features that indicate whether that ruby is natural or synthetic. Let’s say I suspect that the stone is synthetic based on what I see in the microscope. I could then take the stone to the ED-XRF and run chemical analysis on it, where the trace element analysis could confirm whether my suspicions were correct.
Here is what the inside of Lotus Gemology's ED-XRF looks like, this is one of the instruments that'll be used to run chemical analysis on your gems when sent to the lab, this happens to be one of the key elements that'll help determine the origin of a stone, separate naturals from synthetics as well as detect glass filling. - Photo Credits: Lotus Gemology
A polariscope can help us distinguish between singly and doubly refractive stones, and help us determine what kind of interference figure they may have. This can help us separate stones into a few broad categories. Gemology is often a process of elimination. For example, both ruby and spinel are red stones that could be confused. However, ruby is doubly refractive while spinel is singly refractive, so this test would help separate the two.
To get a little more technical, the polariscope can also help you figure out the direction of the c-axis of a stone, depending on the angle that you can see an interference figure. As with many instruments, there is more than one use for this piece of equipment.
A spectroscope will help you see the absorption pattern of a material in the visible light spectrum. This can be helpful to identify certain stones, as well as to check if certain coloring agents are present. Nowadays many labs also use a UV-Vis-NIR (Ultra Violet Visible Near Infra Red Spectrometer), which can provide similar information, but in the form of a spectrum on a graph. We use both methods at our lab.
One thing I’d like to mention here is that as gemology is progressing, many labs, including ours, are acquiring and using increasingly sophisticated equipment. While this equipment is useful, there is still a lot to be said for the value of some of the older and more basic gemological equipment, which can still tell us so much about a stone.
AsiaLounges: There seems to be quite a bit of misunderstanding as to why certain instrument are used. For example: the LIBS unit. How many times have I heard from providers that an untreated, unheated sapphire should be tested for beryllium? While we both know that it would be unnecessary to test an untreated, unheated sapphire for beryllium I’d like you to help our audience understand why it is unnecessary and what is the LIBS unit used for?
Billie Hughes: LIBS (Laser induced breakdown spectroscopy) is a technique that can be used to detect beryllium in corundum. In some sapphires, beryllium (Be) is diffused into the stone to enhance the color. It can create a pleasant orangey Padparadscha-like appearance, or sometimes lighten blue sapphires that appear overly dark.
However, this only happens as part of a high temperature heat treatment process. Thus, when we see a sapphire that has been treated at high temperature, we will test it for beryllium diffusion. However, if a ruby or sapphire is untreated or not heated at a high temperature, it wouldn’t be Be diffused.
It is important to remember that while all Be diffused corundum is high temperature heated, not all high temperature heated corundum is Be diffused.
For y'all graphic fanatics out there, here is a beryllium positive stone tested in a LiBS unit - Graphic Courtesy of Lotus Gemology
Another way to determine whether a stone is beryllium treated or not is by placing them into an immersion cell filled with methylene iodied, as shown here. - Photo Credit: Lotus Gemology
AsiaLounges: Speaking of which, what’s the difference between a FTIR and an EDXRF? What are they used for and how is it possible that, in your opinion, albeit being common instruments between the major labs they give diverging results? What could, in your opinion, cause these issues?
Billie Hughes: FTIR (Fourier-transform infrared spectroscopy) helps us to obtain the infrared spectrum of a material. In gemology, there are many uses for this information. In some cases, it can be used to help identify fillers. The FTIR is also of great utility for analysing ruby and sapphire. Certain FTIR spectra are correlated with heat treatment. Others may indicate that certain mineral inclusions are present in a stone, while others can be an indication of a certain cause of color.
One important note about this is that one cannot effectively interpret this spectrum on its own. A gemologist must combine this spectrum with other data about the stone to get an accurate picture. In certain types of sapphire, a particular FTIR spectrum may indicate heat treatment. In other types of sapphire, the same spectrum may not provide conclusive evidence of heat treatment. This goes back to what I mentioned earlier about looking at all the evidence, rather than cherry-picking pieces, before drawing a conclusion.
In so much of what we do, it is not enough just to see one piece of evidence or information. It is the interpretation of a piece of data, in conjunction with the rest of the evidence, that is important.
EDXRF (energy dispersive X-ray fluorescence) helps us understand the chemical composition of the stone. This can be useful in many ways. Often, it can help us separate natural from synthetic material. It can also help with origin determination. It can also help with things like determining whether a stone has been lead-glass filled.
A gem is about to be FTIR tested by the Lotus team. Some features in the IR spectra can help detect heat treatment in ruby and sapphire - Photo Credit: Lotus Gemology
AsiaLounges: Here’s to two items I know are very important to you personally: the photomicrography station and your latest “toy” the microraman. Could you tell us more about why they are used, what information they provide and, while we’re on the topic: what’s a Raman?
Billie Hughes: Our photomicrography station has a trinocular microscope with a DSLR camera attached. This means that we can capture images of the inclusion scenes we see when the specimens are magnified.
Raman spectroscopy is a technique that provides us with a “fingerprint,” in the form of a spectrum, of different types of materials. This “fingerprint” can be compared against a database of known samples to identify the material being tested.
With micro Raman, we have a Raman laser that is attached to a microscope. Thus in addition to being able to identify the matrix (the overall gem, in this case), we are also able to use the attached microscope to aim the laser at individual mineral inclusions and identify them as well. Using this technology, when I see a crystal inside a sapphire, I can analyse it and determine if that crystal inclusion is apatite, zircon or something else.
I have really enjoyed working with micro Raman. Gemologists often have to make an educated guess as to what kind of inclusion we’re viewing, but a Raman can confirm its identity. We have even discovered a few minerals that have never been reported in corundum before by using this technique.
It’s important to be able to identify inclusions not just for pure curiosity, but also because it can have practical implications on the stones we’re testing. Gems from certain origins tend to contain certain types of inclusions. And some inclusions have only been found in some origins, but not others. With micro Raman, we can work backwards from the inclusions to try to determine where a gem might have come from.
Quite different from the Ramen you have with Tonkatsu pork hey? Here is the mighty MicroRaman, Billie's prized possession at the lab! - Photo Credit: Lotus Gemology
AsiaLounges: Since we’re on the topic of photography, the trade has seen these beautiful shots of yours highlighting the fluorescence of gems. You actually won an award with one of them recently if memory serves. While they make for beautiful photographs and cool posters, I’m convinced that they are showing you guys more than just the beauty of fluorescent stones. Could you tell us more about it and what are the tools you use for that?
Billie Hughes: There is so much we can learn about stones from their fluorescence, and much that we don’t yet know. We use a few different types of fluorescence in the lab to analyse stones.
One is the standard short-wave/long-wave UV light box. This can be great for screening stones or viewing standard fluorescence reactions.
In some cases, we find it helpful to have some magnification. There are a couple techniques we use for this.
We have one microscope that is hooked up to a particularly strong short-wave fluorescence unit, the Magilabs Deep UV Fluorescence System. This is a custom-built unit that our friends at Magilabs developed for us. It has allowed us to see short-wave reactions much more clearly. Some ruby and sapphire that are heated display characteristic short-wave reactions, so this can be a big help in unmasking heat treatment in some stones. In some cases we’ve even seen the characteristic growth patterns of synthetics stand out under this type of illumination, so it can help separate natural from synthetic stones, too.
Sometimes we also use a long-wave UV torch with our microscope. This is a simple and affordable way to see reactions at higher magnification. I’ve written recently about some uses of this technique. It can help, for example, to clearly illuminate fluorescent filler in emerald. With some specimens, like quartz with petroleum inclusions, it can also create stunning effects that make for great photomicrography.
One of Billie's most famous pictures of a ruby taken with the the Magilabs Deep UV Fluorescence System that has been used, among other things as introductory picture by L'Ecole, School of Jewelry Arts supported by Van Cleef & Arpels' recent ruby Exhibition in Singapore - Photo Credit: Lotus Gemology
AsiaLounges: Albeit all these high-tech and costly toys, we often hear lab gemologist tell to their audiences that the most important piece of tech in the lab is the microscope along with a very special ingredient that happen to be rather complicated to replicate and / or purchase: experience. Could you please elaborate on the topic?
Billie Hughes: We’ve talked about how some of the different pieces of equipment in the lab can perform more than one duty. But the microscope is by far the most versatile equipment we use.
Microscopy allows us to study inclusions and get a more complete picture of the stone. Knowing different inclusion features can help distinguish between natural and synthetic gems. Some inclusions can clue us in to what type of gem we’re looking at. In some cases inclusions provide evidence of whether a stone has been treated. This is not limited just to heat treatment, but can include fillers like oil, dye, diffusion, or glass filling. With experience, we can often determine the origins of certain types of gems based on their inclusions.
Of course merely viewing inclusions is not enough. The gemologist must also have the knowledge and experience to be able to interpret what they are seeing. What types of zoning patterns help us separate natural from synthetic stones? Does the appearance of that crystal suggest that it has been heated or not? Are the inclusions in this ruby more likely to suggest that the origin is Madagascar or Myanmar (Burma)? These are questions that a gemologist must be able to answer.
Furthermore, microscopy, like any other test, shouldn’t be viewed just on its own. We look at the microscopic features alongside the spectra, fluorescence, and chemical analysis to draw a conclusion.
AsiaLounges: How many times have I heard from some of my colleagues that the issue of conflicting reports could be settled should the lab agree to follow some sort of standard or talk to one another. Do you guys in the lab industry talk to one another and could that truly be an answer to that issue?
Billie Hughes: There have been some attempts for labs to standardize some of the policies that we have or get together for discussions about important topics. The LMHC (Laboratory Manual Harmonisation Committee) is one group that has issued some guidelines for lab practices. In Tucson every year the ICA (International Colored Gemstone Association) also hosts the GILC (Gemstone Industry & Laboratory Conference), which is a forum where traders and laboratories can get together to discuss current issues. My dad and I have both been speakers at past GILC meetings, and we believe it is important to have a forum where the trade can come together and discuss current issues.
Here in Bangkok some of us labs also get together occasionally for informal discussions, and I think it’s a benefit to the trade that we keep communicating.
But there are issues that are subjective, and thus hard to harmonize. There are already some calls within the same lab that different gemologists will have a different take on, let alone trying to be in sync with other laboratories, some of which will be located in different countries. Issues like how to describe color are a big one we face with harmonization.
In my experience there are some topics that are much easier to agree on than others. When stones are heated to high temperatures, for example, you will likely get a consensus from several labs that it is heated. But for stones heated at lower temperatures, it’s often trickier to make that call.
You also have to keep in mind that much of our work is an educated judgement. There are cases where one report may be flat wrong, but others where I would call two different reports a difference of opinion, rather than necessarily being a mistake. For example, most metamorphic and magmatic sapphire can be separated from each other. So if you had the same sapphire called Sri Lanka (metamorphic) by one report and called Thai (magmatic) by another report, there is likely an error there. But if you have one report calling a sapphire Sri Lanka and another report calling the stone Madagascar, that’s a much tougher differentiation. Sri Lankan and Madagascan sapphires actually grew very close to each other under similar geologic conditions. They only separated later on with continental drift, so some of that material is extremely similar. I would consider the separation more of a difference of opinion.
A further hurdle, even after getting several organizations to agree, is consistency and enforcement.
There are a lot of calls that we make that are subjective, and dependent on the experience of the gemologist. It’s hard to standardize something like experience when we have to make judgement calls.
One thing all the big labs agree on is that natural sapphires have angular growth patterns while synthetics, like in this picture, have curve bending instead... - Photo Credit: Lotus Gemology
AsiaLounges: Following your last answer, do you think that removing colour calls / colour types and origin determination in order to stick to strictly provable data would help labs to be more coherent with one another or is this a fool’s errand either way?
Billie Hughes: Certainly having fewer subjective factors on the report could reduce the number of discrepancies on lab reports on the market, but you wouldn’t eliminate them completely. There may also be ways to modify the way we treat color calls and origin determination that could create more consistent results without doing away with them altogether.
Color types like Pigeon’s Blood and Royal Blue can be highly subjective, so removing those from reports could create more consistency. But it wouldn’t fix the problem of subjective color calls on colored stone reports, because the nomenclature for colored stones has been inconsistent for many years. Many variety names rely on judgements on color. For example, distinguishing between ruby and pink sapphire or green beryl and emerald is subjective. Which tourmalines get called “rubelite” or “indicolite?” Is the trade comfortable with removing “Padparadscha” from sapphire reports?
With regards to origin, moving to broader origin categories might be a middle ground between issuing very specific country of origin comments vs. getting rid of origin. For example, it can be difficult to separate blue sapphires formed in similar metamorphic deposits like Sri Lanka, Madagascar, and Kashmir (India). But the vast majority of these stones are easy to separate from blue sapphires from magmatic deposits like those in Australia and Thailand. Classifying stones in these kinds of categories would be more consistent. Stones from different types of deposits also tend to be more similar in appearance. However, there are always outliers so this wouldn’t eliminate the problem. Furthermore several years ago one of the world’s most well-known lab tried a similar system, and it never really took off. It seems the market was not ready for this type of system.
We must keep in mind that it is not as simple as just collecting data. How the data is collected can have an impact on results. A lot of our work involves the interpretation of data, and this interpretation is depending on the knowledge, attention to detail, and experience of the gemologist.
AsiaLounges: Last question for the road, do you have any advice for the traders and or gem owners out there that have issues with gem reports contradicting each other? Is there a magical formula to avoid that from happening? Is dumping a copy of the spectra enough in your opinion or do you guys at Lotus have a different answer to that particular question?
Billie Hughes: In the case that our clients have any questions about the content of our reports, I always advise them to bring these issues up with us directly, whether it is before or after testing. I understand that there are a lot of misconceptions in the market about gemstone testing, and that many clients don’t understand the inner workings of a laboratory. We are happy to have a conversation about our methods and explain the reasoning behind a particular call.
I have seen many questions, often in online forums, about why a lab might have issued a particular conclusion on their report. I would take some of the advice given with a grain of salt, for the simple reason that it is difficult to understand a call unless you have seen all the evidence upon which that call was based. For our clients, again I encourage you to come to us directly if you have any questions.
It is beneficial to everyone in the gem trade to foster better communication and have a better understanding of gems. We strongly believe in educating the client and in sharing knowledge, which is one of the reasons we have written numerous books and articles about the topic and have shared over 1,000 photomicrographs in our online database, Hyperion.
Regarding just showing spectra on a report, it has been suggested many times that gemological reports should display the data that led to a conclusion. I think just publishing graphs or spectra without context can lead to as much confusion as it does clarity. In our work, it is not enough to just have a spectrum printout. It is the interpretation of this data, coupled with context of the rest of the evidence and the experience of the gemologist that is important.
We are happy to share our data with our clients upon request, but I believe that that data should come with an explanation as well to help the client understand the context. When you go to the doctor, they don’t just show you a scan; they also sit and explain the results to you. I think what we do is similar to that kind of consultation. At our office, we have printed out spectra, taken additional photos, or even pulled equipment into the lobby so that a client can see evidence with their own eyes. Our philosophy is to provide our clients with the kind of information and service that we would expect if we were in their shoes.
AsiaLounges: Thank you very much Billie for being with us today. I am convinced that our readers, the Loungers, have enjoyed this interview as much as we enjoyed writing these lines.
As for us, we will meet you again soon in the Lounges with more exciting content!
If you have enjoyed this interview please let us know by liking, commenting and sharing our work with your family and friends on your favourite social media platform. It helps us a lot and takes but a second!
Should you have any questions or topic that you’d like us to research for a future interviews and articles, feel free to let us know by contacting us at simon@asialounges.com. It is always a pleasure to dig further into the world of gems and gemmology!
For all the rest, feel free to take a look at our gem and jewellery collection as well as to contact us should you be interested in getting one of our famed bespoke pieces of AsiaLounges Jewellery.
See you again in the Lounges,