With that out-of-the-way, let’s dive right in.
Foundational Principle of Disbursement
Once again, this principle is fairly straightforward as it deals with what is required to get a sigil to work. In brief, the rule states that: Sigils require that silver be on the bearer’s person at the time of casting, which is “burned” to fuel the spell.
This is pretty much exactly what it sounds like, although the burned silver does not do anything dramatic like burst into flames. Instead, as the sigil is used the silver is transformed bit by bit into a fine black powder. Because of the apparent similarities between this powder and soot it is said that the silver was “burned” in the process of casting the spell.
Technically the silver doesn’t have to be held directly by the sigil bearer; unlike the sigil itself the silver does not need to be in physical contact with the user. That said, the Foundational Principle of Proximity appears to be very strongly linked to the silver. Even a small separation between the individual and the silver source results in an exponential increase in the amount of silver which must be burned to create a desired effect.
Other details that impact how quickly silver will be burned are how strong of an effect is desired, the distance between the sigil and the intended target, and how proficient the sigil bearer is. The exact cost tends to very from sigil to sigil, and from bearer to bearer, but as a rule of thumb most sigil bearers try to carry a respectable chunk of silver with them. Moreover many noble houses with access to sigil magic keep silver stockpiles, to ensure that interruptions in the Empire’s silver supply won’t hinder their ability to use their magic.