What color is that gem?
This basic question — What color is the gem? – should be answered on every gem appraisal and lab report. It turns out that a couple of related questions also need to be answered:
How did the gem get that color?
And how long will it continue to have that color?
For colored gems—emerald, ruby, sapphire, and the multitude of others—color is the most important determinant of value. Because the most desirable colors fetch higher prices, there is big business in gem treatments, or "enhancements," that turn hum-drum stones into attractive gems than will entice more buyers.
The good: Color treatments can make a poor quality stone look like a gem of higher quality and can even produce attractive gem colors that do not occur in nature. Retailers can offer their customers a larger array of products at affordable prices.
Padparadscha-like color faded over time The potentially bad: If a treatment is not disclosed, the treated gem might be sold and priced as a higher-quality gem, thus cheating the jewelry customer. Disclosure of the treatment, along with appropriate pricing, will avoid this outcome.
The ugly: An attractive color produced by a color treatment may not last! The "enhancement" may simply fade away over time, leaving an unappealing color or just a worthless, colorless stone.
Examples of that "ugly" have not been common, but that may be changing. Several international gem organizations report seeing increasing numbers of rubies and sapphires with unstable color. The hue of the stones was seen to shift over time, even fading to nearly colorless. In one case, the soft, peachy tones of an apparent padparadscha (a high-value gem rarely found in nature) gradually gave way to pale pink.
Those problematic gems had their original color altered through irradiation, and the treatment's source was traced to Sri Lanka. Gemological organizations are now urging more testing for color stability in the Sri Lankan labs and promoting stricter regulation and penalties for labs engaging in undisclosed treatments.
Irradiation has been successfully used to improve the color of many gems. For example, off-color diamonds, those that are yellowish or slightly brown, can be turned to rich green or blue, offering consumers an affordable alternative to the extremely high-priced fancies. The color changes produced are considered stable under normal wear.
Irradiated diamond Irradiation can be tricky to detect. Gemologists often subject suspect stones to a "fade test" by exposing them to intense light for a time and evaluating any change in color. A yellow or orange sapphire that fades in sunlight or with ordinary levels of heat is likely to have been treated.
Lack of treatment disclosure = fraud, a kind of fraud that is increasingly difficult to prevent. Treatments routinely occur far up the selling chain, often before the stone is even cut. The gem supplier may not disclose the treatments, the dealer may not ask questions, the jewelry retailer may not inquire. Lack of disclosure means fraud could occur anywhere along the selling chain.
Consumers, at the end of the selling chain, may not understand the effect of treatments. If they are told their gem is "enhanced," they may take that as a special benefit or even dismiss it as advertising puffery. They may not understand how drastically the gem has been altered to achieve its color and how different its valuation is from that of an untreated gem of similar appearance. Insurers, replacing a treated gem with one that has not been treated, would be overpaying a claim.
All color and clarity treatments should be disclosed. The retailer should also advise jewelry owners of any special care their jewelry may require because of a treatment.
Is irradiated jewelry safe to wear?
According to the Nuclear Regulatory Commission (NRC), gem irradiation takes place in a nuclear reactor (neutron bombardment), an accelerator (electron bombardment), or by exposure to gamma rays in an irradiator. In general, the longer the stones are exposed to radiation, the deeper and more attractive the color. The process of irradiation can make gems slightly radioactive.
Irradiated sapphire This may seem like an excessively dramatic way to change a gem's color, but it happens to be less expensive than some other methods. And it is regulated.
In the US, the NRC requires that these gems be set aside, typically for a couple of months, to allow any radioactivity to decay. The NRC-licensed distributer is required to perform appropriate tests to ensure that no gems are sold to the public unless radioactivity is below levels that could pose health risks.
Any residual radiation is miniscule compared to, say, a chest Xray, and it continues to decay over time. So, scary as it may sound, irradiated jewelry is safe to wear.
Disclosure of a gem treatment/enhancement is important because treated gems have a lower valuation than untreated gems of similar appearance. The valuation difference is especially great for diamonds.
Failure of a color or clarity treatment is not damage for which the insurer is liable.
All color or clarity treatments should be noted on both the appraisal and the lab report.
The appraisal should describe the gem's color in gemological terms of tone, saturation and hue, according to a system developed by GIA. An emerald's color, for instance, might be described as, "Medium Light" tone, and "Very Slightly Grayish" saturation, and "very slightly bluish Green" hue. A vague description, such as green emerald or red ruby or blue sapphire, is not good enough..
Annoying, but true: GIA's own lab reports for colored gems do not follow the color-grading system developed by GIA—a blue sapphire is simply called blue. The report has other useful information, but it's color description is disappointing.
Since an accurate valuation of a colored gem (or its replacement in the event of a loss) depends on a precise description of its color, it's best to have an appraisal that describes the gem in gemological terms as to its tone, saturation and hue.
Carefully check documents for mention of treated, enhanced, or the names of any treatments, such as irradiating, heating or fracture-filling.
The failure of a treatment is not damage for which the insurer is responsible.
Color-treated gems have a lower valuation than gems of similar color that are untreated. For diamonds, the valuation difference is huge.
Non-disclosure can happen at any price point. If the gem has had no treatments, the appraisal should explicitly state that the stone is untreated. This shows that the appraiser has made a determination and not simply overlooked or avoided the issue of treatments.
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