I'd say the answer to this question is out there somewhere, but I'm not quite sure where to start looking for it. The Ars Arcanum for The Hero of Ages lists 14 metals, and at the end of the book, Harmony tells Spook there are 2 more metals to look for. I'm assuming these 2 new metals are Bendalloy and Cadmium since time bubbles are a big part of the new era.
My question is why the original trilogy listed Atium and Malatium as 2 of the 14 metals, but in the new era, these are replaced with Nicrosil and Chromium. I've seen mention of god metals, so I'm assuming that's what Atium was (Ruin = Ati = Atium), but I'm mainly curious as to where Nicrosil and Chromium came from. Seems like there should have been 4 new metals for Spook to find instead of just 2.