Though glass was known to the Egyptians (the monuments showing their mode of glass blowing), it does not appear to be mentioned in the O.T. In Isaiah 3:23 the word 'glasses' ( gillayon ) may signify small tablets of metal to serve as mirrors, such as the women used. The LXX translates it their 'transparent garments.' In Exodus 38:8 it distinctly says that the laver was made of brass out of the women's looking glasses, showing that brazen mirrors were then used. The root of the Hebrew word marah is raah, to see. In Job 37:18 it is from the same root, where the sky is compared to a molten mirror.

The MIRRORis referred to by the word ἔσοπτρον,translated 'glass,' James 1:23 , but the same word is applied to 'glass' or a dim window through , δία, which we see obscurely, as a semi-transparent substance. 1 Corinthians 13:12 . In the Revelation the word is ὕαλος, and is called 'clear,' 'transparent,' and 'like crystal,' which evidently refers to glass. Revelation 4:6; Revelation 15:2; Revelation 21:18,21 . The sea of glass signifies fixed purity. Many specimens of glass have been discovered in the explorations at Jerusalem.

Bibliography Information
Morrish, George. Entry for 'Glass, Looking Glass'. Morrish Bible Dictionary. https://www.studylight.org/dictionaries/eng/mbd/g/glass-looking-glass.html. 1897.

Bible Dictionaries Glass, Looking Glass

Morrish Bible Dictionary

Bible Dictionaries
Glass, Looking Glass