It's right at the very bottom of the Casting Metal tabs. It's not very intuitive, unfortunately. Hopefully they change it in a later update. They should put stuff like Molten Glass in a new separate tab.
Thank yourself lucky, i can't even mine lol, after like 3-4 ores client crashes and i get some dumb error message, idk if it's fixed now but it's how it was like a week ago or something, not bothered recently lol
Sometimes there is more to life than a computer game, R.I.P, YNWA, Never Forgotten