Itemclass - sulphur
From World of Dungeons - Enzykloplaedia
Sulphur is a common reagent used in most, if not all fire magic. Different types of "Sulphur" items tend to have different effects on the spell which they are used to cast.
Example: The fire amulet of Haron the dark gives +4/+8/+16 fire damage. but will only apply this damage bonus to a spell using this item for sulphur.