This metal comes from the wastelands of Avernus, the first layer of Baator, and has seen much use during the eons of fighting in the Lower Planes. Green steel is lighter than normal steel, and is readily worked into razor sharp edges. The yugoloths have taken the opportunity to spread the weapons they’ve acquired throughout the planes, though they are still rare outside the baatezu armies. Piercing or slashing weapons crafted with the green-flecked ore have an increased damage range, as if they were one size smaller.

Banded mail, chain mail, plate mail, and scale mail are the only types of armor that can be made of green steel, and such armor has an increased armor bonus of +1. The market price modifier for such armor is +3,000 gp; weapons made of green steel have a price modifier of +2,000 gp. Baatorian green steel has a hardness of 12 and 30 hit points per inch of thickness.

From the Planescape Campaign Setting on Planewalker