An introduction to gem treatments

As a consumer, you will regularly encounter in the marketplace gems that have been treated to change their appearance. A topic that often comes up is whether a particular gemstone is or isn’t treated. In a sense, humans alter all gem materials after they are found in the earth in order to prepare them for use in jewelry. Natural gem crystals are transformed from their rough crystallographic form into the shapes, outlines, and degrees of polish in the gemstones that we appreciate and wear in jewelry. These steps are and have always been the routine procedures used for manufacturing gemstones. Beyond traditional cutting and polishing, however, gems can often be treated in ways meant to alter their color or clarity. In addition to enhancing their appearance, the process may also improve (or in some cases diminish) the gem’s durability. Because these treatments are not always apparent to the unpracticed eye, and are sometimes difficult to distinguish even by experts, it is necessary and legally required for anyone selling a gem (including consumer to consumer trade) to disclose the treatment procedure it may have received.
Non-disclosure of this treatment could cause a person to believe that a particular gemstone was of higher quality naturally and therefore be more valuable than it actually is. An added challenge is that treatments can be permanent, long lasting, or short-lived under normal jewelry use. Treated gems may require special care by their owner. In the United States, the Federal Trade Commission has established a set of
consumer guidelines outlining the need for treatment disclosures and special care requirements, and countries around the world either adhere to similar guidelines, or have regulations of their own. Additionally there are several professional organizations such as the American Gem Trade Association (AGTA), or the International Colored Gemstone Association (ICA), or The World Jewellery Confederation (CIBJO), that have formulated specific guidelines that their members are required to follow regarding the disclosure of treatments in gem materials. The following glossary includes terms that are often used in the gem treatment nomenclature, and that you may encounter when shopping for gemstones. Finally, treatments for gemstones are constantly being changed and refined, and the detection of these new treated gems is an important part of ongoing gemological research.

The following guide will give a short description of the treatment process, some gems for which the process is used, how easy or difficult the treatment is to detect for a trained gemologist, how often the treated gem might be encountered in the jewelry trade, and how durable the material is to normal handling procedures. Any special care instructions for these treated gems are also provided.

Source: Robert Weldon, www.gia.edu

To learn more about gem treatments see also:

- Gem treatments - Bleaching

- Gem treatments - Surface Coating

- Gem treatments - Lattice Diffusion

- Gem treatments - Laser Drilling

- Gem treatments - Irradiation

- Gem treatments- Impregnation

- Gem treatments - High Pressure, High Temperature (HPHT)

- Gem treatments - Heat treatment

- Gem treatments - Fracture or Cavity Filling

- Gem treatments - Dyeing