Q. What is the refractive index of Tiffany favrile glass?

I consulted Museums Research Scientist Emeritus regarding your interest in the refractive index of Tiffany Favrile glass.Dr. Robert Brill, Research Scientist Emeritus, said:

We analyzed a fragment of Tiffany Favrile glass.  It turned out to be a high-lead glass.  The composition was approximately 57.3% SiO₂, 38.7% PbO, 3.1% K₂O, + some trace elements. I would estimate that the index should be ~1.61.

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Favrile Paperweight Vase with Morning Glories,
Tiffany Furnaces, Louis Comfort Tiffany, Corona,  NY,
about 1913. Gift of Mr. and Mrs. Howard Stein. 97.4.125