'Crystal' in the Bible

The gold and the crystal cannot equal it: and the exchange of it shall not be for jewels of fine gold.

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.

And before the throne there was a sea of glass like unto crystal: and in the midst of the throne, and round about the throne, were four beasts full of eyes before and behind.

Having the glory of God: and her light was like unto a stone most precious, even like a jasper stone, clear as crystal;

And he shewed me a pure river of water of life, clear as crystal, proceeding out of the throne of God and of the Lamb.