ChristianAnswers.Net WebBible Encyclopedia
glass and mirrors
Glass was known to the Egyptians at a very early period of their national history, at least 1500 B.C. (with glass beads dating even earlier). Various articles both useful and ornamental were made of it, as bottles, vases, etc.
The Hebrew word zekukith (Job 28:17), rendered in the King James Version “crystal,” is rightly rendered in the Revised King James Version “glass.” This is the only allusion to glass found in the Old Testament.
In Job 37:18, the word rendered “looking-glass” is in the Revised King James Version properly rendered “mirror,” formed, i.e., of some metal. (Compare Exodus 38:8: “looking-glasses” are brazen mirrors, Revised King James Version).
A mirror is referred to also in James 1:23.