Brimstone

Brimstone (BR), also called sulfur, is a reagent that is in use on Pagan, a yellowish material harvested from the remains of volcanic erruptions which is easily infamable.

Pagan
Unlike the Sulfurous Ash used in the magic systems of Britannia and the Serpent Isle, which is the result of incinerating the brimstone, this is the raw form of the material and it is, because of how volatile it is, used in the magic school of Sorcery. Brimstone is used to greatly increase the power of a spell.