Vin instinctively burning metals is a known fact. She was burning Tin and Pewter without even knowing when she tried to scam March.
In my third read of the book, I notice a small passage, in chapter 24 right after the spook slang joke:
Vin felt…contented. As she sipped at her wine, she caught sight of the open doorway leading into the darkened workshop. She imagined, just for a moment, that she could see a figure out in the shadows—a frightened wisp of a girl, untrusting, suspicious. The girl’s hair was ragged and short, and she wore a simple, untucked dirty shirt and a pair of brown trousers.
Not only vin could see her other self but she also was able to know what she was thinking. It feel more like burning gold to me that just imagination.
It made me wonder if vin did instinctively burn some unknown metals (her that era) like Bendalloy or Cadmium.
This is my first post and English is my third language, I am sorry in advance if I made any mistakes.