Today we interview Nicholas Sturman, currently GIA’s senior manager of pearl identification globally who is based in Bangkok. Nick has over three decades of pearl identification under his belt and is here today to help us understand this very specialized part of the trade.
Our British friend worked on pearls for 16 years in Bahrain before joining us here, in the world gem capital, Bangkok, almost 11 years ago.
Without any further delays we give you Nick Sturman,
Here's Nicholas Sturman wearing a GIA Thailand polo shirt
Asia Lounges: Hi Nicholas, thank you very much for being with us today. Let’s start with our traditional entry, tell us about you. Who are you Nicholas Sturman?
Nicholas Sturman: I am a British citizen who was born in Kenya, East Africa and have spent most of my life living and working outside the UK. I became a gemologist in the mid-1980s during the period I lived in the UK and worked for a while in London at R. Holt & Company in Hatton Garden and then, after an opportunity arose, moved to work for what was known at the time as the Gem Testing Laboratory of Great Britain (AKA London Lab) shortly afterwards. Apart from gems I generally have a fondness for nature and my parent’s, especially my mother’s, passion for orchids definitely rubbed off on me and I have always had an interest in them. My mother even had a species of Cattleya named after her when we lived in Kenya. Sadly it no longer exists as she brought it to the UK with her when we moved to live there and it didn’t like the weather even though she kept it in a heated greenhouse!
Asia Lounges: Could you tell us about your entry in the gem trade and a bit about your career? Where does your lifelong passion come from?
Nicholas Sturman: My passion for gemstones came via my father who was a chartered accountant and worked in different countries (mainly African) every now and again. He was offered a job in Rhodesia (name at that time!) and another in South Africa that were related to mining operations and he brought me back some gold in matrix and emeralds in matrix, which I still have in my collection. That really caught my attention and collecting mineral specimens developed from there. When I left school I entered the trade as quickly as I could and continued with my love of stones. My knowledge and passion for pearls developed from the day I started working for the GPTL of GB. It was a lab that owed its existence to the concerns that centred around the introduction of the bead cultured pearl to the jewellery market in the mid to late 1920’s and at that time its sole goal was to develop ways to separate the Japanese bead cultured pearls from the natural pearls that were the predominant product in the market. There was great concern that it would not be possible to differentiate the new threat from the natural pearls. History proved this was never the case and they could confidently be separated, but it took a bit of time to perfect the various techniques to reach the goal. Anyway, on my first day in 1987 I was basically told that I had to learn about pearls and replace the very experienced staff member who just left the position. The rest, as they say, is history!
As time passed and I developed my pearl testing skills another opportunity arose and I had the chance to travel outside the UK for work. In 1992 as part of my work in the GPTL of GB I was sent to Bahrain as an advisor in the lab that was set-up with the UK lab’s assistance. I eventually stayed there working directly for the Bahrain government and in total spent 16 years in the Gulf country. After that I moved to GIA Bangkok where I have been ever since. So when I find a job I tend to stick around! I haven’t had that many in my career.
Asia Lounges: I believe that prior to asking specific question it may be of interest to clarify our topic a little. Could you please tell us more about pearls in general? What are they and how are they formed?
Nicholas Sturman: Pearls are one of the organic gems found in the trade. They are as popular, some would argue more popular than diamonds, and are often referred to as the Queen of Gems. They form in a variety of molluscs either naturally (without humans being involved in any way) or as cultured pearls (with humans being involved).
A general rule of thumb is that pearls found prior to the 1920s are more likely to be natural, the further you can trace them back the more confident you can be they are natural, while those post 1920’s could be natural or cultured. It gets a little more complex than that as there is more than one type of cultured pearl.
In the trade you may encounter bead cultured pearls (BCP) and also non-bead cultured pearls (NBCP). To add to this you may also find a variation of the bead cultured pearl that are referred to as “atypical bead cultured pearls” (aBCP). Natural pearls form accidentally by natural mechanisms such as the “entombment” of foreign matter that penetrates the shell and finds its way between the shell and living tissue (mantle) or that finds its way into the mantle itself; or results from unknown biological processes within the mantle. BCPs form via human interaction with the mollusc and after conducting an operation within the gonad where a shell nucleus together with a piece of mantle from a donor mollusc (1st operation only) are inserted, whereas NBCPs form after humans insert pieces of mantle from a donor into a host’s mantle. That leaves the aBCPs where a similar process is followed to the BCPs or, should an existing Pearl sac exist after the initial BCPs are produced, another bead (usually another shell nucleus, but could be any atypical material such as a natural Pearl or even a gemstone) is inserted. That probably covers the different types of pearl that exist in the market apart from natural blister pearls, natural or cultured blisters and imitation pearls which I probably don’t need to focus on here or a lot more space will be needed!
Akoya bead cultured pearls such as these shown against a shell background were the first type of commercial cultured pearl to be introduced to the market early in the 20th Century. Photo credit: Robert Weldon/© GIA.
Asia Lounges: As you know, we tend to focus more on the crystalline side of the gem trade, therefore I believe it would be of interest and help our readers understand what determines the value of a pearl. Could you tell us more about that, what makes a pearl more valuable than another?
Nicholas Sturman: Interestingly enough pearls are mostly composed of crystals, so we are not really that far apart!
All shells, and the pearls they produce, are composed of crystals of calcium carbonate polymorphs. This example is a section of a “pen shell” and shows very obvious acicular calcite (per Raman analysis) crystals. Photo credit: Nick Sturman/© GIA.
The calcium carbonate found in pearls is either in the form of aragonite (majority of pearls) or calcite and these minerals are found in pearls as minute crystals arranged with some organic components. As to value there are a number of factors, some we have touched upon already, that make pearls more or less desirable and hence affect their values. Whether they are natural or cultured is important. Natural are, like-for-like, more desirable than cultured pearls, yet BCPs are generally more desirable than most NBCPs. Then we have to consider which mollusc the pearls came from and hence the type of pearl we are dealing with as that has an impact. For example, a fine “golden” Pinctada maxima BCP may be more desirable than a white Pinctada maxima BCP, or a collector may prefer a melo pearl more than any other type of pearl and create a demand for it. Then we have to take into account GIA’s 7 Pearl Value Factors (size, shape, color, lustre surface, matching, and nacre). The better (size = larger) they each are the higher, in theory, the value. Again I could cover a lot of pages just going into each but I think your readers understand the general idea without getting into it in detail. Other factors like “whole pearls” (formed loose in the mantle) being more desirable than blister pearls (formed attached to a shell and have to be subsequently cut from the host to use in jewellery in the vast majority of cases) is “a given” and make complete sense. Then we have to consider those that are untreated versus those that are treated and again the former are generally more coveted. That brings us to what will no doubt be another of your queries!
Asia Lounges: Further to our previous question, I would like to know more about pearl treatments. What should our readers be aware of when purchasing a pearl and how to avoid being tricked, besides bringing you the pearl for identification obviously?
Nicholas Sturman: Some types of pearls are routinely treated, its just the way it is to make them marketable, so for example the majority of akoya BCPs are processed via bleaching and pinking (latter as the name implies is adding a tint of pink to them), while the majority of white to cream freshwater NBCPs are also bleached. These are expected and widely used techniques so are accepted as the norm. I have even seen bleaching carried out in the Gulf on natural pearls, so it is more common than some may think. Other treatments are considered more “negative” by the trade and dealers want to know whether they have been applied to the pearls they submit for identification, so treatments like colour modification (i.e. dye, irradiation, multiple treatment processes), coating, or filling are methods we are always on the look-out for. Readers should just be aware that if something looks too perfect and the asking price doesn’t appear to be realistic there is probably a catch. Buying from reputable dealers who value their name and service is always a safe path to follow.
One of the most commonly applied pearl treatments throughout history is dyeing. GIA includes dyeing and any other process that alters the body colour of pearls under the term “modified color” on its reports. Photo credit: Valerie Power/© GIA.
Asia Lounges: Bit of a personal question now, what is your favourite pearl type?
Nicholas Sturman: That is a tough one! Since I worked in Bahrain for many years I appreciate the natural pearls that the Gulf produced, so they hold a special place for me. Yet, there are so many colourful pearls that exists like the striking purples and oranges produced by some of the freshwater mussels, and the eye-catching pinks of the conch pearls or the unique orange of melo pearls. I suppose if I had to pick one it would be the conch pearl, especially any that approach a strong enough pink saturation to pass as “red” (very rare). The combination of their colour with examples that also show a defined “flame” pattern really stand out!
Pink conch pearls such as this fine example are very popular in the pearl trade. Those of a perfectly symmetrical shape with a pronounced flame pattern and moderate to strong saturation are the most prized. Photo credit: Robert Weldon/© GIA. Courtesy of S. Hendrickson.
Asia Lounges: As you know, the issue of ethical mining and traceability is on everybody’s lips these days. How does the pearl side of the trade view and deal with these issues?
Nicholas Sturman: I don’t believe there are any concerns about such criticisms related to pearls. Clients interested in pearls are more concerned about traceability in the sense of trying to pin-point where the pearls originated because the market values that information rather than avoiding material that may have been farmed in a particular geographic locality shunned by the buying public due to bad press. In summary, I don’t believe that this is something consumers need to be concerned about when choosing their pearls. They can shop without concern in this regard.
Asia Lounges: I have always been under the mistaken impression that both natural and cultured pearls were natural, could you tell us more about the differences between both types and why cultured pearls are not as popular with collectors?
Nicholas Sturman: Natural pearls, as touched upon already, form entirely naturally in mollusc and are found by chance. Many hundreds if not thousands, depending on the mollusc, need to be opened to find one gem quality pearl. When we examine these in the lab using various X-ray techniques to non-destructively view their internal structures we see that they have characteristic growth structures that allow us to identify them as natural, although it isn’t always straightforward. BCPs on the other hand are found in nearly every mollusc opened on a farm, at least one per shell for saltwater farms, and their structures are completely different to the naturals allowing us to separate them easily. The NBCPs start to get a little more challenging when it comes to the identification side, but again every mollusc that is opened on a farm that is working with freshwater molluscs will have multiple pearls in it (20-40). Saltwater NBCPs are another matter as they are only sometimes found as a byproduct and are not usually intentionally produced. So the structural differences we see between the pearls using the various X-ray techniques is enough to easily separate the vast majority of natural, BCP and NBCP types from one another. As for the last query, it is probably not accurate to say “not as popular”, but like everything (art, fashion, automobiles, wine etc….) the best is always in more demand and you have to pay for the privilege of owning it. Hence, natural pearls are perceived as “the best” and are possibly considered more collectable, yet there are poor quality naturals too and very fine quality BCPs and NBCPs (freshwater, as well as saltwater) so there is also a demand for such premium examples of these cultured pearls too. Therefore, I would say that cultured pearls are not totally dismissed by collectors and in fact GIA has issued its top of the range “Monograph Report” on both fine natural and BCP items.
Asia Lounges: When I listen to you talking about the way pearls form, the surgery applied in culturing some commercial species, the type of mollusc etc., it feels like your area of gemology is linked more to biology than traditional gemology. What would be your advice to the new generation trying to follow in your footsteps? What should they study to work with you for example?
Nicholas Sturman: Good observation Simon! There is definitely a strong biology component to pearl work, right from understanding the molluscs anatomy, through to the naming convention used for them, to some testing techniques applied to them, specifically DNA work, it plays an important part of our work. When we look for staff to join the team we make efforts to source those with backgrounds in biology, marine biology or any related science. One team member we currently employ in BKK studied biotechnology at university in the UK and this has proven very useful in some of our DNA related work. The rest comes down to having the right passion and attitude and working as a team if you work in an organization like GIA.
Asia Lounges: This interview is reaching its end and, as it is customary in our columns, I would like to ask you to give three pieces of advice and/or books that you’d recommend to any gem, pearls and jewellery aficionado?
Nicholas Sturman: I think all the great advice has already been shared by the talented members of our trade you have already interviewed. Having a passion for what you do and not just treating it as a “job” is one valuable piece of advice I have always remembered. It is a trait most, if not all you have interviewed share. That is definitely number one on my list. Second would probably be make as many contacts as you can in the trade. Most people are perfectly happy to share information with you if you show the passion mentioned in the first place. Everyone has to start somewhere and learn from someone! Lastly, I would mention a book. Pearls by Elisabeth Strack is the equivalent of Richard Hughes and family’s Ruby and Sapphire and should be in anyone’s library as the go to pearl reference.
Natural pearls such as these two fine examples are often seen in antique pieces of jewellery. However, buyers need to be aware of antique pieces in which cultured pearls have been used as “replacements” or used in convincing reproduction pieces. Photo credit: Harold & Erica Van Pelt/© GIA. Courtesy of Fred Leighton, New York.
Asia Lounges: Thank you very much Nick for this enlightening interview, I hope it was as interesting an exercise for you as it was for us.
As for us, we will be back with you, Loungers, with more cool content soon. In the meantime, if you like what you read here and in previous interviews please like, comment and share these with your loved ones and friends and if you want to support A Gem Dealer's Journal, here is a link to our Patreon's Page.
As usual, should you have any questions you’d like answered, to hear about a particular person in the trade or to be part of one of our next interviews, please contact us at email@example.com and we’ll make sure to give answer you as soon as possible.
Until then, I wish you a fantastic week.
See you in the Lounges,