The pouch is small enough to disappear into a pocket. The disagreement about what it held is much larger. One version calls the dust clay, another brick, another pigment. A fourth leaves open whether there was ever any powder at all.
A travelling reader supposedly marked the floor beneath difficult cards. That is the surviving image: the reading ends, the cards are gathered, and something remains where everyone can see it. Later replicas preserve the pouch more easily than they establish the traveller.
Death, the Tower and the Gate at the Baseline belong to this story of visible consequence. Imagine a pair after an apology. The conversation has ended, but their next arrangement is different: someone else calls the difficult ball, or a formerly automatic decision is discussed. A choice has left a mark without anyone scattering dust.
Most Schools reject sprinkling substances near cards or on courts. The inventory keeps the Pocket of Red Dust as a probable invention and a narrative image; damaging or unsafe imitation adds nothing to it.
The material can remain disputed. What holds the telling together is the moment after the reader has gone, when somebody looks down and notices what is still there.