Ezekiel 1:22

Over the heads of the living creatures there was the likeness of an expanse , shining like awe-inspiring crystal , spread out above their heads .

Spread out above the heads of the living creatures was what looked something like a vault, sparkling like crystal, and awesome.

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.