The ancient process of refining gold has already been described under METALLURGY (which see). Most of the Bible references are to the refining of silver (Pr 25:4; Zec 13:9; Isa 48:10). The silver used by the ancients was probably obtained by smelting lead sulfide ore, rich in silver (argentiferous galena). After the ore had been reduced to a metallic condition, the lead was separated from the silver by blowing hot air over the surface of the melted metal. The lead was thus changed to lead oxide which, in a powdered condition, was driven away by the air blast. The resulting lead oxide, called in the Bible silver dross, was used for glazing pottery (Pr 26:23), a use to which it is still put by Syrian potters. The description of refining in Eze 22:18-22 may indicate that a flux (compare "as with lye," Isa 1:25 the American Revised Version margin) was sometimes added to the melted metal to dissolve the oxides of copper, lead, tin and iron as they formed, thus leaving the silver pure. Crude processes similar to those described above are used in the Taurus Mountains today.

Figurative:

In the various Bible references the refining of precious metals is used figuratively to illustrate the kind of trial God’s children are called upon to go through. If they are of the right metal the dross will finally be blown away, leaving pure, clear, shining silver. If of base metal they will be like the dross described in Jer 6:29,30. The refiner may blow fiercely, but in vain, for nothing but lead dross appears.

James A. Patch