On Thursday, August 6, 2009, Ms. Renée Newman reported on changes in the ruby, sapphire, and emerald trade since first publication of her buying guide in 1991.
Her lecture, was well-illustrated with pictures from her extensive collection, detailed new sources of the stones and, especially, how these stones are enhanced.
She described several new treatments that strengthen color or curtail brittleness. Almost one hundred per cent of stones today are at least heat treated to improve or change color, she reported.
Ms. Newman began her career in the industry after working as an international tour guide. She began her work in gemstones and jewelry in the 1980s by earning a Graduate Gemologist degree from GIA. Her work in the jewelry industry has focused on advising buyers what to look for in gemstones and jewelry because so many of her clients in the tourism industry wanted information on how to tell quality in jewelry.
She started the lecture with a discussion of new geographic sources for rubies, sapphires, and emeralds, citing especially Greenland (rubies), Baffin Island (sapphires), Madagascar (for all stones) and northern Canada (emeralds) as new sites. She then discussed treatments, citing introduction of borax flux to fill cracks (especially emeralds) beginning in the 1990s, use of irradiation to enhance or change colors of sapphires (after 2000), oiling and/or dying of rubies to improve their color, and lead glass filling of rubies (1990s onward).
The use of lead glass fillings, she noted, transforms poor quality rubies into very good quality ones, but the filling does not last. The Federal and many state governments, she said, do not want lead in any substances, so ruby or emerald suppliers will be even more reluctant to disclose such treatment. She warned that one should be wary of a dealer selling large rubies at low prices; they are probably lead-glass filled. Another signal that a ruby might be lead-glass filled is the word “composite”, the word now used to describe lead-glass filled ruby. Another new, important type of treatment, lattice diffusion, she emphasized, changes stones’ colors by diffusing coloring ions into the stone through heat. Heavy ions like titanium or chromium do not go deeply into the stone because of their atomic weight, while lighter ions like beryllium will diffuse deeply into the stone.
Ms. Newman concluded her lecture with some comments on new terms in the industry-especially European use of “modification” in place of enhancement or treatment to describe what has been done to a stone. Another new term is “light green beryl” rather than “poor quality emerald”. Oiling now has two meanings: fill a stone with oil or fill it with oil, wax or resin, or some combination of all three. She also noted that fissure is being used more and more on lab reports rather than fissures. Finally, she bemoaned the closure of AGTA’s lab the week before her talk, another sign of the hard economic times we are living in. The closure will make it more difficult to detect modifications.
The audience of members and guests appreciated Ms. Newman’s lecture and the pictures she showed. There were several questions at the end of her talk which she readily answered, even though she had delivered a lecture the night before in New York City and then traveled to Washington to be with the DCGIA Alumni Association chapter.
Minutes by: Tim Morgan
Photos by: Melanie Marts