You are able to transmute a set of Essentia into Silver using the Crucible. This is useful if you find yourself with a lot of ore you don't want, and you really want some Silver. (Note this is only possible with a mod that includes silver in it, as Thaumcraft has no silver itself and no real use for it).
Do not use ingots for this recipe if possible. Breaking an ingot down into nine nuggets will usually give you more Metallum overall allowing you to get a much more fair conversion ratio. You will lose the "bonus" aspects of the ingots (e.g. Copper Ingot has six Metallum and two Victus vs. nine Copper Nuggets with one Metallum each), though this may not be a bad thing as it also reduces the waste Essentia that might otherwise be released as Flux.
If the source metal is iron, there is no reason not to use nuggets, as Metallum is the only aspect present in iron ingots, and each ingot only has eight, vs. a total of nine for the nuggets.
You are now able to transform other metals into silver nuggets.
Required Research: Basic Transmutation