Residuum

Residuum is arcane dust which occurs naturally in the Astral Plane, and is best described as "powdered magic." It can also be made by breaking down magic items. Residuum is used in the creation of magic items and the casting of spells, and can be used as currency (residuum is described in its gold cost, and approximately 10,000gp of residuum weighs about as much as a single gold coin while taking up only slightly more space).
Extremely pure residuum can be found; its use as the component in a spell will increase the effects of the spell by 1 level, and can produce potentially more powerful magic items.

Dust

In some circles, residuum is illegally consumed as a drug known as Dust. When consumed in this way, taken by snorting through the nose, the residuum induces in its user a strong sense of euphoria and spontaneous magical effects, akin to a wild magic surge, and increases magical potency.