Crystal Heart

Crystal Hearts are objects found on any layer below the surface. When the player breaks a Crystal Heart using a Hammer, or explosives, it drops a Life Crystal which can be picked up. The life crystal can be used to increase your maximum health by 1 heart, or 20 health. It also heals you by the same amount. Crystal hearts cannot be used once one has 400 health, which is the maximum obtainable legitimately.

While they can be hard to find, single-player mode worlds will actually contain dozens more Crystal Hearts than the player can use.

Multiple Crystal Hearts are usually found in the Dungeon and The Underworld.