Perhaps from the same as G5205 (as being transparent like rain); glass: - glass.
Verse
Matrix
Rev 4:6And before the throne there was a sea of glassG5193 like unto crystal: and in the midst of the throne, and round about the throne, were four beasts full of eyes before and behind.
Rev 15:2And I saw as it were a sea of glassG5193 mingled with fire: and them that had gotten the victory over the beast, and over his image, and over his mark, and over the number of his name, stand on the sea of glassG5193, having the harps of God.