Aqua fortis (Latin for "strong water") is the old alchemical name for nitric acid (specifically a solution of nitric acid in water). It was used to dissolve many metals, including silver, but would not dissolve gold.
Game and Story Use
- An alchemist could use aqua fortis as a test for gold (to determine if it is real or fake; if it dissolves, it was fake anyway). This could be useful in an alchemy-heavy campaign, especially one involving chrysopoeia (alchemical gold-making), in which fake gold might flow freely.
- And amusing if the PC who didn't spend the points to be literate confuses it with the Aqua Vitae … or whatever.
- Or better yet, mistakes it for a Potion of Strength.