1) Probably, I hadn't entirely decided.
2) Yes, I'm pretty sure alchemy is a subset of magic in this setting.
3) It's a magical metal. Very soft, very low melting point, contains lots of raw magic, causes madness and sickness if ingested. You'll see several references to it in this thread.
4) Probably, but if so the Amberites keep it very secret.
You're right, that doesn't make sense. I'm not sure what I was thinking and will edit that now.