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 amount of health one is able to obtain legitimately.

It should be noted that crystal hearts can be easily found in the Dungeon, or in The Underworld.