AGL modifies heated-ruby disclosure wording

New York--American Gemological Laboratories (AGL) is modifying the disclosure terminology it uses for treated rubies by exchanging the term "inorganic (fluxtype)" with "heating residues" in its descriptions of heat-treated rubies, the lab announced.In a statement issued on Wednesday, the lab also said it would be including the statement "Heating residues are deposited along healed fractures during the heating process" as an additional description under the comments section of all grading reports for rubies. The way in which the healing of fissures during the heating process of rubies has been handled has been a contentious topic for more than a decade.Rubies are commonly heated to improve clarity and to heal fissures within the stone. As part of the heating process for rubies, it is common practice to coat the stones in a variety of fluxing agents. As the temperature increases, the fluxing agents melt, partially dissolving the ruby's surface and, at the same time, effectively sealing and reducing the appearance of the fissures and improving the general durability of the stone, according to AGL.AGL has traditionally described the enhancement using the following type of terminology: "Clarity: Inorganic (fluxtype)," with additional text that addressed the relative quantity of material that remained, such as "faint," "moderate," etc.Now, AGL says that since the use of fluxing agents during the heating process results in a combination of features or materials being deposited and remaining along the newly healed fissures, the previously open fissures are replaced by planes consisting of re-grown ruby (synthetic), solidified vitreous melt (glass) and voids (empty bubbles). The relative amount of these three parts depends on many factors.To better attempt to communicate the multiple and complex nature of these remaining byproducts, many labs around the world started using the term "heating residues" with terms describing the relative quantity (such as: minor residues in fissures), according to AGL.