This dust exactly resembles that of appearance, and it is typically found stored in the same manner and quantity. 

All things touched by it reflect and bend light of all sorts (infra-red and ultraviolet included) so as to become invisible to sight or virtually any other means of normal detection or even magical means such as detect invisibility spells, but not dust of appearance. 

Invisibility bestowed by the dust lasts for 2 to 20 turns, 11-20 if carefully sprinkled upon an object. 

Attack while thus invisible is possible, always by surprise if the opponent is unable to note invisible things and always at an armor class 4 places better while invisibility lasts. 

Note that unlike the invisibility spell, attack while using the dust of disappearance will not obviate the invisibility.