Bag of Dust
From Warhammer 40k - Lexicanum
Nobody is certain whether the Bag of Dust on Akhor'menet's hip is actually dust from the long-dead bodies of his fellow Thousand Sons, as none have had the courage to ask him. However the powers imbued within the bag are unmistakable. By sprinkling a slight pinch of dust over a bolt weapon he can increase the penetrating ability of the bolt shells within the weapon, increasing the damage they inflict. Somehow, doing this does not deplete the dust within the bag.[1]
Source
- 1: Black Crusade preview, pg. 2