Tales of Tolgard
Steel, an metallurgy of iron and carbon, is fairly common throughout Materia. Most steel is made in a bloomery with charcoal to heat it. However, when more heat is available, higher grade steel can be made.
Keshiki steel is highly prized throughout the world. Because it is forged at a higher heat near the lava beneath Mt Fuego by the fire giants, the steel is an essential ingredient in masterwork weapons and armors.
Keshiki steel is a traded commodity that forms the foundation for economies all over Materia.