Last Updated: Jul 19, 2016     Views: 23

I checked with our research scientist, Dr. Bob Brill, who has done much work in analyzing glass composition and these are his thoughts on your question:

"There is no easy (and still useful) answer to this question. The best means for distinguishing between the two materials is probably by microscopic examination. However, this requires a lot of experience in having looked at many glasses before.

Chemical tests can be definitive, but are not helpful because they either require removing a sample or run the risk of inflicting damage on the artifact. The one exception would be by x-ray fluorescence analysis, but even then that could -- in some circumstances -- inflict solarization damage. UV fluorescence might or might not work depending on the composition of the glass.

Physical properties could certainly be used to distinguish between the two. Refractive indices, densities, or hardness measurements would work but they are hard to conduct if the material is set in a mount of some sort. Moreover, hardness tests would leave scratches on the unkown."

Our library focuses mostly on the art, history and early technology of glass, so our technical collection is not much help in answering this question. If you want to pursue this further, I would suggest you contact one of the following resources:

1)The Scholes Library at Alfred University, New York State College of Ceramics. They have a substantial collection of technical information about glass. Pat Lacourse answers technical reference questions ( Their reference desk number is: 607-871-2951. Their library catalog is available for searching on the web:

2) The Glass Division of the American Ceramic Society (Columbus, Ohio) Website: The American Ceramic Society, P.O. Box 6136, Westerville, Ohio 43086-6136 ; Phone: 614/890-4700 ; FAX: 614/899-6109 ; E-Mail:

3) The Society of Glass Technology in Sheffield, UK: Website:; Don Valley House, Savile Street East, Sheffield S4 7UQ, UK ;Tel: +44(0)114 263 4455 ; Fax +44(0)114 263 4411 ; e-mail:

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