G2930–κρύσταλλος–krustallos

And in front of the throne there seemed to be a sea of glass, resembling crystal. And midway between the throne and the Elders, and surrounding the throne, were four living creatures, full of eyes in front and behind.

κρυστάλλῳ, krustallō “as crystal,”

Then he showed me the river of the Water of Life, bright as crystal, issuing from the throne of God and of the Lamb.

κρύσταλλον, krustallon “crystal,”