AGL: New treated rubies differ from composites

The following article appears courtesy of: National Jeweler

A new ruby treatment has been entering the market from Thailand over the past year and while it is similar to a composite ruby, it can't be classified as such, according to the American Gemological Laboratory


New York–The American Gemological Laboratories (AGL) is alerting the trade to its studies on a new ruby treatment that combines fissure healing and in-filling to improve the stone’s appearance, but that is distinct from the type of treatment that “composite rubies” undergo.  
According to a press release from AGL, this new ruby treatment–which provides a low-cost alternative to more traditionally heated rubies–has been detected in stones, mostly from Mozambique, which are treated in and exported from Thailand. The treatment is “reportedly a modification of the lead glass or composite ruby treatments that have emerged in the past,” according to the release.

Composite rubies–a term coined by AGL–began flooding the international gemstone market in 2003, and subsequently made their way into the U.S. market, where they have more than once become the subject of investigative news reports aimed at alerting consumers to the potential pitfalls of purchasing such stones. The controversial stones, which are lower-priced goods that require special care and specific disclosures to consumers, are an amalgam of natural ruby with a high lead-glass content.

For the new treatment, AGL has learned that a selection of the rough material suitable for the composite ruby treatment is treated using various chemicals or fluxing agents, similar to the more traditional heating of ruby that results in fissure healing and heating residues.

AGL President Chris Smith said in the release that after encountering the new treatment, the lab was initially unsure of whether to: classify the stones as “composite rubies;” describe the treated rubies as having undergone the more traditional format of fissure healing, involving the quantification of heating residues; or come up with yet another new form of disclosure.

During AGL’s investigations, it became evident that in some samples, fissure healing was taking place, whereas in other samples there was less healing taking place, but open fissures were still being in-filled with glass-like material–although no lead or bismuth was detected as would be expected of a typical composite ruby.

According to the release, AGL has decided not to classify this new treatment as composite ruby on its grading reports. Nor will the lab develop another new classification for disclosure of this treatment.

Instead, the lab will expand the disclosure information for its reports on these stones to better represent the dual nature of what happened to the stones as a result of the treatment process. For those stones where the majority of what occurred during the treatment process was the healing of fissures, the traditional disclosure nomenclature addressing the quantity of heating residues will be applied.

For those stones where a significant extent of what occurred during the treatment process involved the in-filling of fissures in combination with fissure healing, the disclosure wording will address both heating residues and in-filling, with an expanded description provided under the comments section of the lab report, the release states.

Initial durability tests indicate that these new-treatment stones have fewer special-care requirements than composite rubies and that their characteristics more closely resemble those of traditionally heated rubies possessing heating residues when exposed to conditions in a jeweler’s workshop or commercial household products.

“It is our opinion that the wording policy put in place for this material provides a practical approach for the industry and labs to address these stones and maintain that adequate disclosures are being made available to consumers,” Smith said in the release.

Full details on the policy are available at


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