"Long enough ago that they just have names now and nobody's needed to worry about it in thousands of years. Except nickel, but that's a contraction of a phrase that means 'fake copper' in... I forget, I think it was a language spoken in some little corner of an Imperial-speaking country but I can't remember if it was Capchen or somewhere else and I don't remember what the language is called. Or if it still exists. So I guess we could name the new stuff after a metal that already exists, 'magic steel' or something. But I feel like that would get confusing."