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AGL, GRS Collaborate on Descriptions for Lead-Glass Treated Rubies

Oct 3, 2011 1:06 PM   By AGL
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Press Release: Ever since the lead-glass treatment of ruby/corundum hit the market nearly 10 years ago, there have been issues over how to describe and represent this material for the trade and laboratories alike. GemResearch Swisslab (GRS) and American Gemological Laboratories (AGL) have come together to begin harmonizing the description of these stones on their respective gemological reports.

''We wanted to let the gemstone and jewelry industries know that GRS and AGL have begun working in a spirit of collaboration between our labs and we believe that the controversies surrounding how these stones are described on our reports is a perfect venue to demonstrate this,'' said Dr. Adolf Peretti, the president of GRS Laboratories.

Christopher P. Smith, the president of AGL, said, ''Increasingly over the past several years issues surrounding the clear representation and disclosure of this material have come to the forefront around the world.  Both GRS and AGL believe that this treatment needs to be clearly distinguished on our reports from the more traditionally heated rubies that are available in the marketplace in order to avoid confusion between these two products.''

Since the lead-glass treatment of low-grade ruby/corundum began entering the market in 2003, literally hundreds of thousands of stones have been sold globally. Gemologists, gemological and trade associations, as well as laboratories around the world have extensively published, lectured and generally communicated how to recognize these stones and the inherent issues of durability that surround this treatment, as well as the need for proper disclosure.

In November 2007, AGL took a high-profile position by coining the name Composite Ruby to describe all lead-glass treated ruby/corundum, while in 2010 GRS started using the name Hybrid Ruby for the same purpose.

Several features make these stones readily recognizable by anyone with little training and a loupe or microscope. Internal characteristics such as contraction bubbles in the glass, a distinct bluish and orangey color flash and the golden to red body color of the lead-glass make these stones easy to identify without the use of a gemological laboratory or advanced analytical testing. In addition these stones are not durable. Lead-glass treated ruby/corundum may be strongly damaged by some ordinary household products and routine repair by a bench jeweler.

However, the interwoven nature of ruby and glass-filler in addition to the very close refractive index of the high lead-content glass to that of the corundum makes it difficult to determine exactly how much glass versus ruby/corundum is present in each piece.

''In our opinion, it does not make sense to create different levels of how to describe these stones, as a lay person will be unlikely to make some of these distinctions on their own,'' Peretti indicated. ''Most of these stones are so heavily in-fused with lead-glass that many believe they should not even be associated with the name of ruby.''

Smith said, ''Regardless of the extent of the lead-glass treatment, these stones are readily recognizable by anyone with little training and simple observations, meanwhile all carry the same essential issues of durability and special care requirements.'' 

As a closing statement, both Peretti and Smith emphasized: ''We believe that developing a collaboration between GRS and AGL will be a benefit to our individual companies and the industry in general. In our view the association of the names Composite Ruby and Hybrid Ruby as a means to represent these leadglass (bismuth-glass) treated stones will provide our clients with the means to easily recognize and distinguish them from the more traditionally heated ruby on our reports.''

As of October 3, 2011, all GRS and AGL reports for lead-glass treated ruby/corundum will read as follows:

GRS Identification:
Synthetic Glass/Treated Ruby (GRS-type “Hybrid Ruby”)
Comments: Heat-treated and filled with a colored foreign solid substance (including lead).  Special care required when handling. Also known as Composite Ruby.

AGL Identification:
Composite Ruby
Comments: This stone is a composite of natural ruby and a high lead content glass. Also known as Hybrid Ruby.*
*See Enhancements section of the AGL report for additional comments related to the durability and special care of this product.

About GRS GemResearch Swisslab Laboratories
GRS Laboratories is a group of gem testing laboratories first founded in 1994 in Switzerland with additional GRS gem testing laboratories subsequently opened in Thailand, Sri Lanka and Hong Kong. GRS is specialized and has become renowned world-wide for its origin and quality reports on rubies, sapphires and emeralds. Its laboratories are positioned very closely to the world’s most important gem markets. GRS publishes its independent gemological research in its own journal: Contributions to Gemology and produces unique documentary video content on topics related to expeditions and research on the source of colored gemstones (

About American Gemological Laboratories
American Gemological Laboratories (AGL) is the United States’ most widely known and respected colored stone gem identification and quality grading laboratory. It was founded in 1977 and became the first gemological laboratory in the US to provide quality grading as well as country-of-origin determinations for colored stones. AGL has become an iconic brand for uncompromised standards and excellence in gemstone reporting (

Rapaport News is not responsible for, and does not endorse, the content of any press release. Press releases are not written by us and are provided only as additional information for our clients.


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Tags: AGL, composite, glass, Labs, lead, ruby, treated, treatments
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