a costly deep blue gemstone, almost certainly lapis lazuli rather than the clear blue jewel English now calls sapphire
This is the Bible's name for one particular precious stone, and the English word it inherited points at the wrong rock. The stone Israel knew was almost certainly lapis lazuli: an opaque, intensely blue stone flecked with gold colored grains, quarried far to the east and carried west by trade for thousands of years. What English now calls sapphire is a transparent crystal so hard that no ancient tool could cut it, and there is no sign it was mined or worked anywhere in Israel's world until centuries after these books were written.
The ordinary uses in the text fit the softer blue stone rather than the modern gem:
- It is mounted in the second row of the high priest's breastpiece, so it was cut and set by hand.
- Song of Songs pictures it inlaid into carved ivory, the decorative work lapis was famous for.
- Isaiah promises a ruined city foundations laid with it, treating it as building material.
- Job places it in the ground beside gold dust, which reads naturally as the gold colored specks running through lapis.
The other half of the word's life is comparison. Three times it describes not an object but a sight: the pavement under God's feet at Sinai, clear as the sky itself, and the throne Ezekiel twice glimpses above the living creatures. In each case the writer reaches for the most valuable blue thing anyone could name in order to say what an otherwise indescribable vision looked like. Lamentations does the same with human beauty, comparing the look of Jerusalem's young men to the stone before hunger ruined them.
It rarely appears alone. It sits in lists of costly stones whose identities are quite as uncertain as its own: the stone beside it in the breastpiece row (נֹפֶךְ), the stone named after the distant place called Tarshish (תַּרְשִׁישׁ), and the one Job pairs with it when he says wisdom cannot be bought (שֹׁהַם). Ezekiel, describing the throne, calls it simply a stone (אֶבֶן) of this kind and lets the color do the work.