Glass is mentioned in Ether 3:1: "And they were white and clear, even as transparent glass." Critics have claimed this to be too early (Tower of Babel) for the invention of glass. However according to Roy Weldon, modern discoveries make this objection easy to answer today, but a few years ago it would have been necessary to accept this statement on faith alone, for there was little actual evidence available to the scientist.
According to the Encyclopedia Americana, glass objects were manufactured as early as 3000 B.C. The University of Chicago has a pale green cylinder of glass dating from this period. [Roy E. Weldon, Book of Mormon Deeps, Vol. III, p. 302]
“Transparent Glass”
Ether 3:1 states that the stones were white and clear, even as transparent glass." According to Randall Spackman, any given glass composition "can exist in different energy states dependent upon its structure." . . . Williams has noted that "one of the most striking features of luminescent emission [is] that it occurs for most substances in the spectral region where the crystal or glass is transparent." Whatever the physical properties of the sixteen small stones, through the faith and action of the brother of Jared and the intervention of the Lord, the stones shone in the dark with sufficient luminescence that the Jaredites were willing to enter the barges and set forth across the Pacific. [Randall P. Spackman, "The Jaredite Journey to America, p. 130, unpublished]
“Even as Transparent Glass”
Joseph Smith described the interpreters (which later generations have termed Urim and Thummim) as "two transparent stones set in the rim of a [silver] bow fastened to a breastplate." The term "transparent" is used only two other times in the scriptures--in the descriptions of the glowing stones used by the Jaredites (see Ether 3:1) and of the streets of gold of the New Jerusalem that John saw descending from heaven (see Revelation 21:21). In both cases, the full description is "as . . . transparent glass." In this connection, it is interesting to note that the heavenly city has foundations made of twelve precious stones and also twelve gates of pearls (see Revelation 21:19-21). This reminds us of the twelve stones in the high priest's breastplate, and indeed, John noted that the names of the twelve tribes were inscribed on the twelve gates (see Revelation 21:12), just as the names of the tribes were inscribed on the two stones worn by the high priest (see Exodus 28:9-12). John further wrote that the heavenly Jerusalem had "the glory of God; and her light was like unto a stone most precious, even like a jasper stone, clear as crystal" (Revelation 21;11). Because the heavenly Jerusalem will be lighted by the glory of God, it will have no night and will need neither sun nor moon (see Revelation 21:23-25). The heavenly city is very much like the residence of God and the future celestialized earth, as described in Doctrine and Covenants 130:6-9." A globe like a sea of glass and fire . . . a great Urim and Thummim . . like unto crystal."
It is also interesting to note that in Targum Pseudo-Jonathan on Exodus 19:17, Mount Sinai, when the Lord's presence was upon it, is described as being "transparent like glass." [John Tvedtnes, The Book of Mormon and Other Hidden Books: Out of Darkness unto Light, pp. 203-204]