Four Metals

One of the Schola societies, they are focused on crafting, with a particular devotion to various of the crafting deities (Athena, Minerva, Hephaestus, Vulcan, Brigid, etc.) 
Their focus includes fibre arts, handcrafts, and other skills as well as metalwork, but they draw much of their membership from Salmon House and include many people who end up as Materia specialists. 
The Magic of Four discusses people invited to the Four Metals during the 1946-1947 school year.