d647950c_d___Game_Guide_and_Walkthrough__BONE_CHARM_PROPERTY
[BONE CHARM NAME] Spirit Water [USEFULNESS] I recommend that you wear it only if you have no better solutions connected with mana regeneration. [BONE CHARM PROPERTY] 
Drinking tap water slightly regenerates your mana.
Bone Charms - list - Collectibles - Dishonored - Game Guide and Walkthrough
BONE CHARM PROPERTY