Wasn’t it a bit strange for the brother of Jared to ask the Lord to make stones glow?

First of all, the brother of Jared prayed in faith, believing that he would “receive according to [his] desires” (Ether 3:2). This means that he trusted that “with God nothing shall be impossible” (Luke 1:37). And the Lord honored his faithful request.

Secondly, the brother of Jared may have remembered an earlier example: Noah’s ark. The Lord told the brother of Jared that his barges could not have fire or windows (see Ether 2:23–24), but the Bible says that Noah’s ark had a “window” (Genesis 6:16). However, the word translated as “window” may not have actually been a window. Some rabbis and other scholars have said the ark’s “window” was a precious stone that shined in the ark (see Genesis 6:16, footnote a). The story of Noah’s ark probably would have been known to the brother of Jared. (The Jaredite record included an account covering the Creation down to the tower of Babel [see Ether 1:3–4].) So the brother of Jared’s request may not have been all that unusual.