Sulfurous Ash

Sulfurous Ash (SA) is the residue left by sulfur which has been set alight, which is used in the magical practices of Britannian and  Serpent Islander magicians.

History and Uses
Elemental sulfur is frequently found in the wake of volcanic activity, and as a result is plentiful on the Isle of the Avatar and its neighbor Terfin, both of which have been sites of eruptions. According to Philpop the Weary's  Book of Mystic Wisdom, the element gives forth its magical properties after it has been burnt in a crucible fashioned from a balron's skull, and the resultant residue or "ash" may then be used as a magical reagent. In spite of such fantastical claims, raw volcanic sulfur appears to suffice on both Britannia and the Serpent Isle as a magical component, where its presence lends properties of energy, heat and light to spells which incorporate it. 

Trivia

 * Sulfur, when burnt in reality, reduces itself to a red liquid, rather than leaving behind an ash. The fumes from burning sulfur, as Joe Garrity from the Origin Museum discovered in an ill-planned experiment whilst producing a real world reagent collection, are quite toxic, and were used as a method of fumigation in archaic Greece.