I'm rereading Bands of Mourning and in chapter 5 I came across this passage. Wax and Steris are on the train to New Seran. Steris is reading a book and Wax tried to get her attention.
This immediately reminded me of Sazed and Tindwyl studying their copperminds in Well of Ascension. They would zone out while they did. I know people can get engrossed in a book. But wait, there's more!
When Wax managed to get her attention, she seemed to be in a fog. He asked her a question:
My thinking is he asked her a question and she accessed a coppermind for the answer.
I know it's popular to speculate that Steris is this or that misting/ferring. I also know Brandon has said she's on the Autism/Aspergers spectrum. But these quotes struck me as odd.
I searched through Alloy and Shadows and couldn't find any similar examples of Steris either tapping a coppermind, or wearing visible copper. But let's be honest, she would never show it. Also, she was captured by the Vanishers, and not killed for her investiture. So, it's admittedly a flimsy theory. But I found it interesting.
tl;dr Steris is an Archivist (copper ferring). It would certainly compliment her spectrum disorder. It could help explain her amazing ability to make lists.