Revelation 4:6
and before the throne was as it were a sea of glass like crystal; and in the midst of the throne and about the throne were four living ones [cherubs] full of eyes before and behind.
Revelation 4:3
And he that sat was like a jasper and sardine stone, and there was an iris about the throne, similar in appearance to an emerald.
Revelation 21:11
having the glory of God; its luminary was like the most precious stone, like a crystalline jasper.
Treasury of Scripture Knowledge
Summary
And the likeness of the firmament upon the heads of the living creature was as the colour of the terrible crystal, stretched forth over their heads above.
The likeness
Bible References
The likeness
Revelation 4:3
And he that sat was like a jasper and sardine stone, and there was an iris about the throne, similar in appearance to an emerald.
Revelation 21:11
having the glory of God; its luminary was like the most precious stone, like a crystalline jasper.