I is for iridized glass, and its shimmering rainbow effect. A thin metallic layer is bonded to the glass when a metallic salt solution is applied and then heated. Dichroic glass, which means “two color” is sometimes confused with iridized glass, but it is a coating that allows the glass to toggle back and forth between only 2 colors. The pale yellow glass, second row from the outer edge in this mandala, is iridized, and you can see the subtle purplish sheen of the rainbow coloration. Tiffany patented a version of iridescent glass called “Favrile” which was applied to his blown glass artworks. Here is an excerpt from Mark Doty’s apt poem, titled Favrile:
Glassmakers,at century’s end,compounded metallic lusters
in referenceto natural sheens (dragonflyand beetle wings,
marbled light on kerosene)and invented namesas coolly lustrous
as their products’scarab-gleam: Quetzal,Aurene, Favrile.
Suggesting,respectively, the glazeof feathers,
that sun-shot fogof which halosare composed. . .