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 Post subject: Lotus Gemology lab alert
PostPosted: Fri Apr 03, 2015 2:56 am 
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very interesting report from the Hughes Family......

http://www.lotusgemology.com/index.php/ ... oiled-gems

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 Post subject: Lab Alert for Oiled Gems
PostPosted: Fri Apr 03, 2015 10:47 am 
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Lab Alert for Oiled Gems
For immediate release

3 April 2015—Over the past few months gemologists at Bangkok's Lotus Gemology have noticed a disturbing increase in the number of gems submitted for testing that have been subjected to fissure filling with oils/resins. This situation has now reached the stage where a trade warning is in order.

In our opinion, it is not the place for gemologists to decide what is and is not acceptable in terms of treatments. Certainly there is a place in the market for natural, treated, synthetic and imitation stones. That said, we have had a string of clients who, upon being told their stones have been fissure-filled, were visibly displeased. Not a single one was informed about the presence of this treatment at the point of memo or sale.

Standard operating procedure at Lotus Gemology is to ask customers at the time of take-in if they believe their stones are treated, and if so, by what method. Since opening our doors in July 2014, we have not had a single client declare to us that the ruby, sapphire or spinel they were submitting was filled with oil/resin. In virtually all cases, when we inform the customer that the stone is fissure-filled with an oil/resin, they ask to have the gem back so the filler can be removed.

We believe this speaks volumes, suggesting that at the Bangkok wholesale trade level, both sellers and buyers are unaware their goods have been oil/resin treated. Thus the purpose of this trade alert is to inform buyers so they can make educated decisions. At the same time, we want to inform sellers that they may have a problem with their suppliers, who have not properly informed them of the treatments applied to the gems purchased. Finally, we believe it's important to inform gemologists around the world to be on the lookout for an enhancement that they might not be fully aware of.

In doing so, we will also take this opportunity to describe some of the methods by which fissure filling with oil/resin can be detected. One of our core beliefs is that knowledge belongs to no single company or person, but is the collective property of all humans. Thus we are happy to share the following information on the methodology that we use to detect fissure filling.
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 Post subject: Re: Lab Alert for Oiled Gems
PostPosted: Fri Apr 03, 2015 11:10 am 
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Lovely.

I did notice the following:

Lotus Gemology (emphasis mine) wrote:
Some in the "don't worry, be happy" camp have suggested that this is not deliberate oiling, but simply oil from the cutting/polishing process forced into fissures. Sadly, the evidence to date strongly suggests that this is not the case. First, oil is not commonly used in the cutting process for either ruby, sapphire or spinel. Second, we have seen filled fissures where the filler is so deep that it appears to have been applied via heating/vacuum. While we try to always maintain an open mind, the available evidence strongly suggests that this is being deliberately done to improve the appearance.

Are they referring to commercial cutting? While I love a certain grumpy guy's water-based diamond polishing sticks, oil is the norm in precision faceting when using charged laps.

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 Post subject: Re: Lab Alert for Oiled Gems
PostPosted: Wed Apr 08, 2015 4:23 am 
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The oils in for instance DiaSticks do not by any means penetrate fissures in the way we can see in the treated stones. Also the oil base used when cutting is commonly color coded as well as opaque and the oils we are seeing is transparent and almost colorless. I have seen oil oozing out of fissures in Mozambique rubies when heated by a ordinary light bulb.

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 Post subject: Re: Lab Alert for Oiled Gems
PostPosted: Fri Jun 05, 2015 10:06 am 
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I suspect that filling goes farther than rubies, sapphires and spinel. Anything with a surface reaching fracture could and likely IS fracture filled. Oil, polymer....whatever is handy.


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 Post subject: Re: Lab Alert for Oiled Gems
PostPosted: Wed Jul 08, 2015 10:42 pm 
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upcyclist wrote:
Lovely.

Are they referring to commercial cutting? While I love a certain grumpy guy's water-based diamond polishing sticks, oil is the norm in precision faceting when using charged laps.


Commercial cutters in Thailand typically do not used charged laps. What we are seeing is deliberate oiling and the problem is almost entirely limited to Burma and Burmese gems. It is so prevalent that my daughter has joked that we should use it as an origin criteria.

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 Post subject: Re: Lab Alert for Oiled Gems
PostPosted: Wed Sep 09, 2015 12:34 am 
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Barbra Voltaire wrote:
I suspect that filling goes farther than rubies, sapphires and spinel. Anything with a surface reaching fracture could and likely IS fracture filled. Oil, polymer....whatever is handy.


Yeah, we have seen quite a lot of fracture-filled tourmalines as well. Rubellites are the common "victims".


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