This item gives stats when adding to Bethany's soul charges.
Although The Lost can pick up soul hearts, he will not gain any stat boosts from picking them up.
This item is useless for Keeper, since he cannot encounter soul hearts.
Hearts acquired prior to picking up Soul Locket will not provide stat boosts.
If Soul Locket is removed (such as with Tainted Isaac), stat boosts will not be removed.
Glowing Hour Glass: Stat boosts acquired by soul/black hearts will not be lost after Glowing Hour Glass is used, allowing the same hearts to be picked up multiple times. The bonuses are added to the same stats, in the same order as before using the Glowing Hour Glass.
This item is the soul heart equivalent to Candy Heart, and gives twice as many stats per heart collected comparatively.
When exiting and continuing a run, all stat gains previously obtained by this item are lost.