https://en.wikipedia.org/wiki/Lapis_lazuli

BLUE

There are many references to sapphires in the Old Testament, but most scholars agree that, since sapphire was not known before the Roman Empire, they most likely are references to lapis lazuli. For instance, Exodus 24:10: "And they saw the God of Israel, and there was under his feet as it were a paved work of a sapphire stone…" (KJV). The term used in the Latin Vulgate Bible in this citation is "lapidus sapphiri", the term for lapis lazuli.