The American Heritage Dictionary defines crucible as "a place, time, or situation characterized by the confluence of powerful intellectual, social, economic, or political forces; a severe test of patience or belief; a vessel for melting material at high temperatures." A crucible was the vessel in which medieval alchemists attempted to turn base metals into gold. That the alchemists inevitably failed in their audacious attempts doesn't denigrate the power of the crucible as a metaphor for the circumstances that cause an individual to be utterly transformed.