GOLD AND SILVER are among the most widespread symbols in the history of religions. Their exceptional physical qualities make them—like their celestial counterparts, the sun and the moon—unusually powerful symbols of spiritual realities. As a physical substance, gold is quite literally incorruptible: it is highly resistant to chemical reactions and is immune to the corrosion that affects baser metals. It is also intrinsically luminous, seeming to shine with a light of its own. Thus no speculative leap was required to make gold the universally acknowledged symbol of life and the spirit and of perfection and immortality. There is a certain obviousness to the symbolic value of gold that explains its universal appeal throughout history and in virtually every corner of the world.

Silver too is naturally suited to serve as a religious symbol. Its faultless whiteness has made it a symbol of...