Splitting damage is done by powerful puncturing blows, usually in arcing motions, often to penetrate armor. These attacks are done with a combination of force and the small surface area of the weapon, for example a pickaxe.
Splitting uses your Strength modifier.
For resistances and vulnerabilities Splitting counts as 50% Piercing & 50% Bludgeoning
Modifier: Strength
Damage Type: 50% Piercing, 50% Bludgeoning
Penetration: 2
Damage die: Medium