Heartstone

Heartstones are crafted by Night Hags from the heart of a humanoid. The essence of the creature's soul is ensnared in it's heart at the point of death with foul magics. The heart is then compressed into a black stone that the Night Hag polishes as she spends the next month chanted spells over it. At the end of the process the lustrous black stone allows the Night Hag to use the remains of the creature's soul to access the ethereal plane. The concentration of a creature's final moments of life also gives the stone the power to boost the lifeforce in others. A person touched with the stone will be cured of all diseases, but at a price. At the moment someone is healed, the nearest person close to them emotionally will be infected with a wasting sickness that will kill them within a month.
Clerics of good aligned deities have developed a ritual that can used to cleanse a heartstone, removing the horrible side-effect of using the stone while retaining at least some of the power. These cleansed stones can cure diseases infecting a person once a week, and will not infect others with a wasting disease.

Weight

1 lb