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

Read Ezekiel 1:22 Using Other Translations

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.
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 them was a surface like the sky, glittering like crystal.