GLASS
(a) (Heb. “querach”, ice: this is often translated).
Ezekiel’s expansion over the living creatures was “like a marvelous crystal” (Ez. 1:22).
(b) (Gr. “krustallos.”) John saw a sea of glass like crystal (Rev. 4:6); the jasper stone was “clear as crystal”; and the water of life “clear as crystal” (Rev. 21:11; 22:1).
Ancient glass could be “transparent” in the sense of having no imperfections, without having been completely transparent.