Fine Jewelry by Francis & Linelle Lynch

Lead-glass-filled rubies have been a hot topic since they became widely available in the gem trade and made their way to retail stores, jewelry websites, and TV shopping channels. AGL has adopted the term composite ruby to distinguish this material from traditional heated rubies, while recognizing that it is neither an imitation ruby nor a synthetic. This treatment significantly impacts the original corundum’s appearance (perceived transparency and color), and special care is required to avoid damage to the stone.

 

Despite the prevalence of this material in the marketplace, we were still surprised by an antique pendant that was submitted for identification. The pendant did not appear to be a replica, and the workmanship was indicative of an older piece. It was set with old-mine-cut diamonds and seed pearls, consistent with its apparent age, but we identified the center stone as a composite ruby, with an estimated weight of 7.5 ct. The composite ruby had been carefully reset (the milgrain around the bezel was in good condition), and we saw no degradation of the glass in the stone that could be caused by the jeweler’s torch.

 

The fact that this material has started to show up in antique jewelry is representative of how far it has penetrated the market and reinforces the importance of proper identification and disclosure.