A gem dealer's journal — heat treatment

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.

Hey Loungers, Many have mentioned that we do not interview enough females in these columns. While I disagree, I find myself interested to study a new pattern in our trade: The Path of Inheritance in the Trade, is it a curse, a boon or a bit of both? To that end, we have decided to interview Kamila Guerchouche about her new brand, Kaerche and used this opportunity to ask her a few questions about her path as a second generation gem dealer. If you are as interested in that story and potential new questioning arc, follow us with this very...

Hey Loungers, You often hear us talking about Thailand, and Bangkok in particular, as being the beating heart of the gem trade yet never really explained why. Well, today, we can finally help you get a better grasp over the importance of Thailand for our merry trade. Today, we have the pleasure of introducing you to one of Chantaburi’s Lords of the Ruby trade. Today, we have the pleasure of interviewing the owner of the titanic Gemburi company, the jovial and outgoing Phuket Khunaprapakorn! Khun Phuket, the floor is yours!   Discover Gemburi's K. Phuket Khunaprapakorn story now as a...

Hey Loungers, Today we have a rare opportunity for you. Today, we take you with us in the very heart of the heat treating industry of Chantaburie with none other than our pal Karim Guerchouche from Premacut. Karim has been on the forefront of heat treatment for decades now and is one of the most knowledgeable experts around when it comes to the heat treatment of rubies. Karim’s company is known to serve some of the major players of the Place Vendome in rubies, whether directly or indirectly and has a selection of gems treated and natural that are beyond...