What It Actually Is

Aurum Potabile resists a single modern chemical identification precisely because it was never one fixed preparation: genuine versions correspond either to a dilute solution of gold chloride or a related gold salt, or to a true colloidal suspension of metallic gold nanoparticles, both real and technically achievable, while a documented and substantial fraction of what circulated commercially under the name is now understood, from period criticism and later analysis where available, to have contained no gold at all, a straightforward case of historical fraud rather than a genuine identification problem. This makes aurum potabile a useful example of the difference between a substance whose name is ambiguous because history is unclear, like sal ammoniac, and a substance whose name is ambiguous because it named a claimed medicinal effect and a marketing category as much as it named any single fixed chemical preparation, a distinction historians of alchemy such as Lawrence Principe draw explicitly when cautioning against assuming every gold-named preparation in the historical record actually contained gold. Where a specific historical recipe survives in enough detail to analyze, whether it describes real gold chemistry or not, this atlas treats that detail as decisive over the preparation's reputation or price, which were never reliable guides to its actual contents.