Sublime Bone Dust locations
Sublime Bone Dust #1 - Heide's Tower of Flame
This if found right at the beginning of the region. After taking out the first giant knight, move up the staircase nearby. You can loot this off the corpse hanging off the railing to the right.
Sublime Bone Dust #2 - Sinner's Rise
When you take the elevator down to the water level in Sinner's Rise, take the first left. Past the nasty enemy is a corpse holding this item.
Sublime Bone Dust #3 - Undead Purgatory
This is found when crossing the suspension bridge from Huntsman's Copse (near the Undead Lockaway bonfire). After crossing, leap to the corpse on the right ledge to loot this.
Sublime Bone Dust #4 - Iron Keep
After defeating the Old Iron King, enter the very next chamber to find this inside a chest.
Sublime Bone Dust #5 - Black Gulch
After defeating The Rotten, you'll enter a tunnel. Take a right at the fork to find a chest containing this.