Just a neat little idea. Only the Light and Life elements have 2 shields, which seems a little unbalanced for the rest of the elements. A diversity of shields also greatly increases the strategy potential of this game. Thus, my card idea is an Earth "Shield", a 'Main Gauche', or parrying dagger. It's supposed to block weapon attacks for the cost of 3 Earth. It doesn't block Flying Weapons, though - only whatever is in your weapon slot. It also deals 1 damage to the opponent per turn. Useful, and an interesting new strategy to implement if I do say so myself.
If image is unviewable, the main idea is this:
Main Gauche - 3 Earth Quanta
Shield: Attacking weapons are blocked. Deal 1 damage to your opponent at the end of every turn.