gems, corundum, treatments.4, glass filling

Glass-filled rubies have been reported in the gem trade for several decades (e.g. Kane 1984), with Pb-bearing glass being the most common material documented for filling fractures (McClure et al. 2006). In recent years, however, increasing concerns regarding health, environmental and durability issues associated with Pb-rich glass have driven the development of alternative Pb-free glass fillers. This note documents two different such fillers encountered in heat-treated rubies that were recently submitted to GIT’s Gem Testing Laboratory: a barium-zirconium-yttrium (Ba-Zr-Y) silicate glass and an erbium (Er)-bearing silicate glass. Both have diagnostic visual, spectroscopic and chemical characteristics that distinguish them from previously reported glass fillers.