Each gemstone-testing lab currently employs its own language to describe lead glass–filled rubies. American Gemological Labora­tories calls the ­material “composite ruby,” with an additional comment: “This stone represents a composite of natural corundum and glass, also known as Hybrid Ruby. Additional comments—The material is ­heavily treated…vastly ­improving the ­apparent clarity and adding weight. With special care warnings.”Gemological Institute of America labels the stones “a ­manufactured product.” The report continues: “This item is a ­combination of ruby and glass. The binding material may be unstable to elevated temperatures and ­chemical agents. Special care should be taken when cleaning or repairing ­composite materials.”Prior to December, the GIA called the material “ruby with glass or ruby/glass composite or natural corundum with glass or na