Photomicrography > Corundum > Glass-filled rubies
First draft: May 15th, 2014 | Last update: March 18th, 2016
Diagnostic Features of Glass-Filled Rubies
Lead (Pb) Glass
Lead (Pb) glass filled rubies started to appear on the market during the early 2000s. Gem labs responded promptly by issuing lab alerts covering all characteristics of the new kid on the block, but the treatment evolved further. In the beginning, only Malagasy material was used, but that has changed.
Secondly, fractures were only thin fissures back then, and dealers were very reluctant to admitting that these stones were treated with glass. But today stones containing more than 60% of glass are encountered. Such stones are called reconstructed ruby.
While it seems that a semantic discussion is unfolding about whether or not rubies should be classified as reconstructed or composed, it is clear that the treatment is both drastic and conspicuous enough to ask yourself the question whether this material should actually be called ruby.
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Legend: FoV: Field-of-View; DoF: Total focusing depth; DF: darkfield; Obl: oblique illumination (fiber optics); Refl: reflected light; Pol: polarising filter before objective; Sh: shadowing; TM: transmitted illumination, UVL: long-wave ultra-violet radiation; UVS: short-wave ultra-violet radiation; X-Pol: crossed polarising filters