Time and again, the limited ability of human beings to discern another person's inner quality from their outer appearance proves to be both the obsessive theme and ironic device of William Shakespeare's theatre (1564-1616). Despite its innate deceptions, it seems that Shakespeare leveraged the medium of the theatre to explore the very problem of false appearances and to formulate a metaphorical structure to give voice to the anxieties about this pervasive epistemological problem. Following the estimated chronology of the plays, one may trace an abiding and even intensifying interest in the problem of trust in appearances – specifically, the problem of discerning good character from bad character behind the mask of appearances – or, as Shakespeare would put it, the discernment between “pure,” “noble,” and “base” natures, by which characters very frequently praise or chastise one another or themselves throughout the plays, as we shall see. However, as this chapter will explore, the opposition between these words refers not only to a moral division, but a division between metallurgical categories – specifically, a reference to the “purity” of “noble” metals such as gold or silver, unmixed with “base” metals such as copper, tin, or lead. In Shakespeare's plays, this way of denoting value in a person's character was not merely an ornamental metaphor, but an imaginative model by which to parse ethical realities. It was a model that mapped out a strategic stance towards the moral and psychological problem of penetrating through false appearances to the inner truth of someone's character, based on the real possibility of doing so with physical metals, so that one can even read Shakespearean plots through this lens.