Elemental Strikes

You add different elemental damage to your weapon dependent on what kind of damage the weapon does. 

As you hold your Slashing weapon in your hand, a thin sheet of flames shoots forth from your blade with each strike you make for one round of combat. Each creature in a 20-foot line must make a Dexterity saving throw. A creature takes 1d6 fire damage on a failed save, or half as much damage on a successful one.

The fire ignites any flammable objects in the area that aren't being worn or carried.

As you hold your piercing weapon in your hand, a thin sheet of ice shoots forth from your blade with each strike you make for one round of combat. Each creature in a 15-foot cone from the entail contact point of the attack must make a Dexterity saving throw. A creature takes 1d6 frost damage on a failed save, or half as much damage on a successful one.

The ice freezes any liquid objects in the area that aren't being worn or carried.

As you hold your bludgeoning weapon in your hand, a thin sheet of stone shoots forth from your blade with each strike you make for one round of combat. Each creature in a 10-foot sphere must make a Dexterity saving throw. A creature takes 1d6 bludgeoning damage on a failed save, or half as much damage on a successful one.

The ground where each strike lands is difficult terrain for one round.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the duration is increased by 2 rounds per spell level it is cast.