The firmament/molten looking glass sky is biblical and  stretched forth/spread out as a tent for the earth's inhabitants to dwell in.

Genesis 1:6-7 KJB
And God said, Let there be a firmament in the midst of the waters, and let it divide the waters from the waters.
And God made the firmament, and divided the waters which were under the firmament from the waters which were above the firmament: and it was so.

The heavens declare the glory of God; and the firmament sheweth his handywork.
Psalm  19:1 KJB 

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.
Ezekiel 1:22 KJB

Job 37:18 KJB
Hast thou with him spread out the sky, Which is strong, and as a molten looking glass?

𝔅𝔦𝔟𝔩𝔦𝔠𝔞𝔩 𝔽𝔼