Four attributes, plus luck.
STRENGTH : Melee damage +1
DEXTERITY: Ranged damage +1, Hit% +1, Dodge +1%
INTELLIGENCE: Elemental (magic) damage +1, Resistance (magic) +1
STAMINA: Heart of life effect +1 (wheh you are full life, grabbing an Hearth of life will improve your total Health to the number of stamina points).
LUCK: chance to find better items and gold