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.

Bible References

The likeness

Ezekiel 1:26
And above the firmament that was over their heads was the likeness of a throne, as the appearance of a sapphire stone; and upon the likeness of the throne was a likeness as the appearance of a man upon it above.
Ezekiel 10:1
Then I looked, and behold, in the firmament that was over the head of the cherubim there appeared above them as it were a sapphire stone, as the appearance of the likeness of a throne.
Exodus 24:10
And they saw the God of Israel; and there was under his feet as it were a paved work of sapphire stone, and as it were the very heaven for clearness.
Job 37:22
Out of the north cometh golden splendor: God hath upon him terrible majesty.
Revelation 4:3
and he that sat was to look upon like a jasper stone and a sardius: and there was a rainbow round about the throne, like an emerald to look upon.
Revelation 21:11
having the glory of God: her light was like unto a stone most precious, as it were a jasper stone, clear as crystal:

American Standard Version Public Domain