Job 28:5,6 - Joseph Benson’s Commentary on the Old and New Testaments

As for the earth, out of it cometh bread Out of the surface of the earth man gets herbs and corn, and other kinds of food for his sustenance: and under it is turned up, as it were, fire Lime, to manure and enrich the ground, or coals and brimstone, and other materials of fire: unless, as some suppose, this rather refers to a central fire in the bowels of the earth. The stones of it are the place of sapphires Of precious stones; the sapphire, as one of the most eminent, being put for all the rest. In some parts of the earth the sapphires are mixed with stones, and cut out of them and polished. And it hath The earth containeth; dust of gold Distinct from that gold which is found in the mass; both sorts of gold being found in the earth.