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Altered Beauties: Gem Treatment

It’s very easy to feel spellbound by the first glimmering gem that you see in the jewelry case. How could Mother Nature produce such a vivid blue sapphire? Or, take a look at that stunning princess cut emerald! However, before you purchase that emerald pendant, make sure you are making an informed purchase. To do so, you need to know about gem treatments.

Every natural gem comes from a piece of “rough.” Rough refers to the original rock or mineral chunk discovered and retrieved from the mine.

Example of ruby rough | Photo from GIA

Example of ruby rough | Photo from GIA

Example of a finished ruby | Photo from GIA

Example of a finished ruby | Photo from GIA

Expert gem cutters and manufacturers than examine each piece of rough in order to assess how best to cut and polish it to yield the most marketable and attractive gemstone(s). Quite often, however, those gemstones still need a little “help.” Much to the chagrin of an unknowing consumer, the gems we see in the department store jewelry case are not always naturally quite so rich in color or “flawless” in clarity. Sometimes, they need to be enhanced through treatment. These treatments should be disclosed during the purchase of your jewelry. Even if it isn’t, it’s safer to assume that the gem has been subjected to treatment, unless examined by a professional gemologist and reported otherwise.

By the technical definition provided by GIA, gem treatments are any human-controlled processes beyond the typical cutting and polishing of a gem during the manufacturing process that improves the appearance, durability, or value of a gem.

Heat treatment is a common example method used as a gem enhancer. Typically executed in kilns or ovens at temperatures ranging from 200-2000 degrees Celsius, the gems are packed within a crucible, along with sand or a similar material in order to allow the material to heat up slowly and avoid thermal shock. The high temperature allows for electrons within the crystal structure to move and form different bonds, resulting in a change of electron valence and hence, a different color (

Sometimes, other elements or factors are also introduced to the treatment process. In the case of rubies, the controlled presence of oxygen in the kiln during heat treatment can actually result in a purer red with a reduction in the purple tint. Heat also has the capability of melting or dissolving certain inclusions in the ruby and helping to heal and close internal fissures. So overall, the outcome is a redder ruby with the appearance of improved clarity. Keep in mind, that heat treatments can sometimes involve additives. This too, should be disclosed during the gem purchase. Sometimes, inclusions within a ruby are fixed by filling it with a lead glass. Emeralds, in turn, are sometimes filled with oil or resin, to disguise the appearance of internal fractures. “Some estimates state that 90 percent or more of emeralds are fracture-filled” (GIA, Emerald Care Cleaning). Such additives should be kept in mind when having jewelry cleaned or repaired. Ultrasonic cleaners are a great tool utilized by jewelers to efficiently and effectively remove dirt and grime build-up from your jewelry due to daily wear. However, the vibrations from this device or even the heat from steam cleaners can loosen the fillings from fractured stones, or cause oil and unhardened resin to sweat out.

This brief discussion on gem treatments is not meant to frighten or deter you from buying jewelry with gemstones. If executed and disclosed properly, gem treatments simply allow your gemstone to achieve its highest aesthetic potential, and you just have to be mindful of how treatments will impact the way in which you should care for your jewelry. Just because it’s treated does not mean your gem is any less real (unless it’s synthetic or simulated—but that topic is for another day). It may, however, explain the pricing of a piece you’ve been eyeing.

Macy's Fine Jewelry Page

Macy’s Fine Jewelry Page

A major factor in gem pricing is its rarity. A genuine, natural ruby that has been certified as unheated will certainly command a premium, because it is so commonplace to treat that stone. Admittedly, other factors such as gem size, fair trade, and responsible sourcing will indeed come into play, as well, during gem pricing and purchases. Overall, however, I think it can be said that treatments broaden the accessibility of beautiful looking gems for consumers and jewelry aficionados.





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