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Gemstone Enhancements – Make Sure You Know What’s Been Done to Your Stone!
Many gemstones are treated with various chemical and physical processes to improve their appearance. These enhancements include; dyeing, bleaching, coating, filling, heating, heat diffusion, irradiation, and more recently, laser drilling.
The Federal Trade Commissions (FTC) guide for the jewelry industry mandates full disclosure of all gemstone treatments and that the disclosure be easily understood by a reasonably intelligent consumer. For example, merely stating that a sapphire has been heated is not sufficient, the effects of this treatment on the stone, the permanence of the process, any special care requirements and the effect on the stones value should all be disclosed.
Gemological laboratories caution that consumers should be aware of two types of enhancements, traditional and additional. For example a gem may be heated, a traditional enhancement and then oiled to mask fractures, an additional treatment.
In the last few years there has been a resurgence in the use of thin film coatings to improve the color of many stones. Pink, Yellow and Orange Diamond specimens have all been identified by the labs as have many Tanzanites. The labs estimate that coating a Tanzanite can improve its color grade by one to one and a half grades, more than doubling its value. The fancy colors of Topaz are almost always due to coatings that have been applied to the stone and it is vitally important for the consumer to realize that the most of these treatments are not durable and can easily be scratched or removed by chemical cleaning.
The practice of filling cracks in rubies using lead glass has become increasingly common in recent years and now that the embargo against Myanmar (Burma) material is in place, this practice will become even more popular as unscrupulous vendors look to make use of whatever pre-ban material that they can. Lead filling can increase the selling price (not the value!) of the material by two hundred fold.
Another gemstone that is frequently enhanced is the Emerald. Typically very included, the Emerald is a Type III gemstone and various oils and resins are often used to enhance the stones clarity and reduce the appearance of fractures. This treatment is non-permanent and can easily be removed during cleaning. Over time, the oils will often evaporate on their own, returning the stone to its original state.
By the way, given the number of hands that a gem passes through overseas before being offered for sale to you, information received from a gem wholesaler regarding the enhancement methods applied to a given stone is not guaranteed to be accurate no matter how reliable the supplier may be. Oftentimes, small numbers of treated stones are slipped into larger parcels of good material and it is very difficult for even the best of the large suppliers to test all of the stones they receive.
For this reason, Du Lyon Jewelers believes that it is vitally important to You, the customer, to make a full disclosure of what we have been told about the stone and then go one step further by taking the arduous extra step of actually confirming it. Every Investment or Statement gemstone (or set) that Du Lyon purchases and makes available to you is analyzed by an on-staff GIA Graduate Gemologist. Any and all treatments identified by the supplier are verified and then the GG examines the gemstone for evidence of enhancement techniques that may not have been called out. If they uncover anything that makes the stone not "natural" or "un-treated" Du Lyon will identify that treatment to you.
In the case of very expensive or rare stones, Du Lyon will often times send the stone to an outside Gemological Laboratory for evaluation and positive identification of the stone. In this way the customer can be assured of the real value of the stone, the value having been established by an independent professional with no vested interest in the sale of the stone.
If the stone that you wish to purchase does not already come with a lab certificate from an outside lab you can always request that one be obtained. There is a charge for the Gemological Laboratory to perform the analysis and issue the certificate, typically $35 - 100 depending on the lab and the identification services requested. Please contact Du Lyon for more details about this service.
In the end, always remember to work closely with your gem supplier to get detailed information on the specific enhancements that have been applied to your gemstone - and do it before you purchase the stone!
For more information on Gemstone Enhancement Methods:
Gemstone Enhancement Methods
The Federal Trade Commissions (FTC) guide for the jewelry industry mandates full disclosure of all gemstone treatments and that the disclosure be easily understood by a reasonably intelligent consumer. For example, merely stating that a sapphire has been heated is not sufficient, the effects of this treatment on the stone, the permanence of the process, any special care requirements and the effect on the stones value should all be disclosed.
Gemological laboratories caution that consumers should be aware of two types of enhancements, traditional and additional. For example a gem may be heated, a traditional enhancement and then oiled to mask fractures, an additional treatment.
In the last few years there has been a resurgence in the use of thin film coatings to improve the color of many stones. Pink, Yellow and Orange Diamond specimens have all been identified by the labs as have many Tanzanites. The labs estimate that coating a Tanzanite can improve its color grade by one to one and a half grades, more than doubling its value. The fancy colors of Topaz are almost always due to coatings that have been applied to the stone and it is vitally important for the consumer to realize that the most of these treatments are not durable and can easily be scratched or removed by chemical cleaning.
The practice of filling cracks in rubies using lead glass has become increasingly common in recent years and now that the embargo against Myanmar (Burma) material is in place, this practice will become even more popular as unscrupulous vendors look to make use of whatever pre-ban material that they can. Lead filling can increase the selling price (not the value!) of the material by two hundred fold.
Another gemstone that is frequently enhanced is the Emerald. Typically very included, the Emerald is a Type III gemstone and various oils and resins are often used to enhance the stones clarity and reduce the appearance of fractures. This treatment is non-permanent and can easily be removed during cleaning. Over time, the oils will often evaporate on their own, returning the stone to its original state.
By the way, given the number of hands that a gem passes through overseas before being offered for sale to you, information received from a gem wholesaler regarding the enhancement methods applied to a given stone is not guaranteed to be accurate no matter how reliable the supplier may be. Oftentimes, small numbers of treated stones are slipped into larger parcels of good material and it is very difficult for even the best of the large suppliers to test all of the stones they receive.
For this reason, Du Lyon Jewelers believes that it is vitally important to You, the customer, to make a full disclosure of what we have been told about the stone and then go one step further by taking the arduous extra step of actually confirming it. Every Investment or Statement gemstone (or set) that Du Lyon purchases and makes available to you is analyzed by an on-staff GIA Graduate Gemologist. Any and all treatments identified by the supplier are verified and then the GG examines the gemstone for evidence of enhancement techniques that may not have been called out. If they uncover anything that makes the stone not "natural" or "un-treated" Du Lyon will identify that treatment to you.
In the case of very expensive or rare stones, Du Lyon will often times send the stone to an outside Gemological Laboratory for evaluation and positive identification of the stone. In this way the customer can be assured of the real value of the stone, the value having been established by an independent professional with no vested interest in the sale of the stone.
If the stone that you wish to purchase does not already come with a lab certificate from an outside lab you can always request that one be obtained. There is a charge for the Gemological Laboratory to perform the analysis and issue the certificate, typically $35 - 100 depending on the lab and the identification services requested. Please contact Du Lyon for more details about this service.
In the end, always remember to work closely with your gem supplier to get detailed information on the specific enhancements that have been applied to your gemstone - and do it before you purchase the stone!
For more information on Gemstone Enhancement Methods:
Gemstone Enhancement Methods
Submitted on: May 11, 2009 @ 1:07pm
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