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A Gem Dealer’s Journal: Who has their paws in the oil jar?

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Dear Loungers,

We have been busy recently and couldn’t write as much as we wanted, but be sure that some market updates are on the way.

I was recently asked what to look for while buying a gem and it got me thinking. Although I wrote an article on the topic about a year ago, with the extra experience I gathered in the meantime, I figured I could throw in a couple more tips. And so, as you may have heard already, nature hates empty spaces about as much as the gem market does and it delivered a few cookies on my doorstep. Must be the effect of the Lovers’ season...

In the last few months, I witnessed how several gems, primarily rubies and spinels, were oiled, yet no mention of such treatment was ever indicated on the gemological report they carried. It was puzzling and a cause for alarm as it could put our ecosystem to risk. Hop on and see how can this peculiar issue can be solved while keeping everyone happy.


This round gas bubble is suspended in a small cavity on a Burmese ruby which has some filler substance (this could be resin or oil). Oil is often used to mask the appearance of fissures and cavities

"This round gas bubble is suspended in a small cavity in a Burmese ruby which has some filler substance (this could be resin or oil). Oil is often used to mask the appearance of fissures and cavities" - Photo by E.Billie Hughes for Lotus Gemology 


While being common, accepted, and disclosed on gemological reports in the emerald business, very few know or have even heard of a similar occurrence in the ruby and spinel trade. While from a philosophical stand point I have no issues with the treatment of gemstones, I do have a problem with its non disclosure.



Who’s to say that one should only purchase natural, untreated stones when the budget or need may not allow? I, myself, do on occasion provide my clients with gems that are treated, but I also advocate for full disclosure of treatment and origin. (See here for an example of heated gem sold and advertised as such).


Example of emerald sold as being treated with actual gemological certificate stating the treatment. Photo by Arjuna Irsutti Photography for AsiaLounges


So how do we get these clean reports on oiled stones? When asked, most labs answer that the treatment was applied after the release of the report and, when questioning the owner of the gems, they obviously know nothing about it either… Who is to blame and how can we solve this issue since there appear to be no guilty paws in the oil jar?

The problem lies in the fact that, more often than not, the oil is applied directly on the rough in order to make it look more appealing to potential buyers. Seasoned rough merchants are usually aware of such tricks and will often clean the rough as best they can before deciding whether they should proceed with the purchase. We can therefore deduce from that habit, that the oiling of rough does have a visual incidence on the gem material. Heck, if it did not, why would they bother doing it?

Some (very few, hopefully) of my colleagues will say that I am making a mountain out of a molehill, that it has always been done, so why change now? Lab gemologists, who are prone to call out the crafty nature of dealers but less happy to be called out on theirs, will highlight that they warned about this issue in 2015 and are actively calling an oiled stone oiled. While all this is true, it is also true that many also call dealers to give them a chance to clean their stones, before issuing the final report, knowing full well that their clients will re-oil the stones the second they are out of the lab. Or at least some who have been been called in repeatedly for the same issue will...


Oil in burmese spinel

"In Myanmar it has become common practice to oil virtually all gems that contain fissures. Here we see oil-filled fissures dripping oil in a spinel from Mogok." Photo by Richard Hughes for Lotus Gemology.


For a lot of people in the industry, it’s a numbers game. For the previous, they make an extra buck while the latter… well, they do too, but mostly they are afraid of losing a client to less scrupulous labs that might accept to say that the stone wasn’t treated… All in all, its the short sighted idea that a meal today is worth more than a livelihood tomorrow that prevails', and this needs to stop.


Colored Oil in Ruby by Lotus Gemology

This ruby has been treated with red oil to disguise the appearance of fissures. Here it has been trapped in a cavity with a large gas bubble. Photo by E.Billie Hughes for Lotus Gemology


How could a foreign filling substance, whether colored or not, not affect the clarity of a gem? Why would we feel it necessary to advertise the level of oil in emerald, because it enhances the appearance of the gem, but not in rubies, sapphires, spinels or any other gems for that matter? Doesn’t it serve a similar purpose from a visual stand point? Isn’t that supposed to help increase the price of a gem that would, otherwise, not be nearly as pleasant?

Here at AsiaLounges, we believe in transparency, and value honesty above all else. While we are not the only ones in this position, we guarantee to our clients that, should they find a treatment that was not originally disclosed on the gemological report provided with the stone, we would then refund them as stated in our terms and conditions.

Many in our industry are working hard to keep things clean; it is our role, as actors in this industry, to ensure it remains so by being exemplary with our clients as well! 

Now, what can one do in case of doubt or conflicting reports on a ruby, sapphire or spinel? The first thing I would do is contact the current owner of the gem and ask him to clean the gem in acetone. Traditionally, acetone and alcohol are used to clean gems, emeralds, for example, from their treatments. 

At this point, figuring out whether the mistake was genuine or intended should be easy! Should the oiling be intentional, the owner will normally refuse to clean the stone in front of you as it may have a serious impact on the overall look of the gem.

However, if the mistake was unintentional, the gem dealer shouldn't have a problem with cleaning the stone for you, in your presence, and have the gem tested again by the lab that originally detected the oil. 

While all this may delay the purchase, as well as having a minor economical impact in the form of a second or third gemological report, what's an extra week or two and a hundred dollars on a gem worth several thousand? 

Stay tuned for more  interesting news about the world of gems and its actors!

See you soon in the Lounges,

Asia Lounges

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