Canny

The knowing stone — dark, reflective, and able to hold the sharpest edge on earth.

Obsidian · The Law of Pursuit

Family: Volcanic glass — rapidly cooled felsic lava
Hardness: 5–5.5 on the Mohs scale
Colour: Jet black, sometimes sheened gold or rainbow
Signature: Conchoidal fracture — edges finer than surgical steel

The stone read as the word

Obsidian breaks in smooth shell-shaped curves, and the edge left behind can be finer than a scalpel; surgeons have used obsidian blades for exactly that reason. It is the stone that cuts because of how it knows to break.

Polished, it becomes a mirror — the earliest mirrors in the world were obsidian. Canny is that pairing: the shrewdness that cuts cleanly, and the surface that shows her her own face while she does it.

What it is carried for

Carried when cleverness has aged into knowing.
Held before she explains a thing — and discovers what she still does not know.