18. Red coral (Eze 27:16).
      pearls--literally, "what is frozen." Probably crystal; and Job 28:17 will then be glass.
      rubies--UMBREIT translates "pearls" (see La 4:1; Pr 3:15). The Urim and Thummim, the means of consulting God by the twelve stones on the high priest's breastplate, "the stones of the sanctuary" (La 4:1), have their counterpart in this chapter; the precious stones symbolizing the "light" and "perfection" of the divine wisdom.

JFB.