Dreg is an exotic material found primarily on the moon of the same name orbiting Mote. It naturally emits a field of antimagic powerful enough to neutralize the power of starstuff.
The moon of Dreg is the original source of dreg ore, which can be found at all layers of the moon's body. If one could overcome the incredible difficulties of getting off of Mote's surface, surviving on the airless Dreg for an extended period, and escaping its massive antimagic field, collection of the material would be a relatively trivial effort.
Dreg does not degrade into other forms and can endure wide ranges of temperatures in a solid state. Ore deposits exposed to air or violent impacts will erode into smaller grit.
Dreg naturally emits an area of antimagic (as in the antimagic field spell) and thus can serve as a means of suppressing spells and magical effects within close proximity. The antimagic area's radius scales with the amount of accumulated dreg: a Tiny chunk of dreg emits a 5-ft. antimagic field, and this field's radius extends by 5 feet for each size category above Tiny. The Esterfell Accord has been trying to acquire dreg to study the practical application of these effects, but the ore's extreme rarity in Esterfell has slowed any such research.
Dreg's antimagic effect has a unique property when interacting with starstuff: any such material left within the sphere of dreg antimagic will permanently convert into more dreg after 1d4 hours. This effect only occurs if the volume of dreg is equal to or greater than the volume of starstuff; for example, a Medium chuck of starstuff can only be affected in this manner by a Medium or larger chunk of dreg. The high value of starstuff and the permanency of the conversion generally discourages this use.
Dreg is a stable substance with an indefinite shelf life, but precautions must be taken to prevent its antimagic field from nullifying other magical objects within proximity.