What are Some of the Treatments of Gemstones?
In a sense, every gem undergoes some type of treatment in transforming them into valuable stones. But while cutting and polishing a stone to bring out its natural color and beauty is readily apparent in the finished stone, some other types of gemstone treatments are not so apparent, even to the experts.
There is a legal requirement to disclose any type of gemstone treatment a stone may have received before selling it to a gemstone buyer. However, no every gemstone dealer is completely honest. If you're new or inexperienced in the gemstone business, you might rely on an expert to assure you of getting what you pay for. Or, you can request an authenticity report from a certified gemstone testing laboratory. Any reputable gemstone dealer will be happy to supply you with these reports.
Types of Gemstone Treatments
As hard as a gemstone appears to the naked eye, a lot of them are relatively porous. They respond to bleaching, fillers, dyes, heat treatment, lasers, irradiation and coating different chemicals to alter their color, opacity, surface smoothness and other factors.
Not all of these treatments are done to deceptively increase the value of the gemstone. Pearls, for instance, are routinely lightened with hydrogen peroxide to make them more uniform in appearance. As long as the seller and buyer are both aware of this technique and have accepted it as a normal step in the preparation of pearls, there is no problem.
Dying is also a known type of gemstone treatment that is applied to pearls. However, in dying the pearls, the purpose is to artificially enhance their value, which is deceptive and illegal unless the buyer is informed of the practice by the seller.
Cavity and Fracture Filling
One of the most deceptive gemstone treatment techniques is to fill the surface of harder gemstones with materials like glass, polymers, resins and oils. The treatment reduces the visibility of the crevice, cavity or fracture and artificially makes the facets of a gemstone look completely flawless unless the gemstone is examined closely and carefully.
Rubies, tourmaline, aquamarine, topaz and emeralds are some of these harder, faceted gemstones that are often subjected to this type of gemstone treatment.
Thankfully, this technique is not as prevalent as some of the other gemstone treatments, as it can be easily spotted by a qualified gemologist viewing the gemstone under magnification.
Because these treatments exist and straddle the line of acceptability, it's reasoning enough for someone new to the gem trade to proceed cautiously in their purchases and sales. Ask for a recent authenticity report for your gemstone purchases and ensure the gems you’re offering for sale have them as well.
Keep in mind that an old authenticity report is fairly useless in the detection of gemstone treatments, as these treatments could have been administered after the issuing of the authenticity report.
Your best bet is to establish a trusted relationship with a gemstone testing laboratory and make use of their expertise regularly.
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