Shin | Torment Tides of Numenera Wiki

Shins are shiny, coin-like objects treated as currency in the Ninth World.

Shins are usually metal but can be made of glass, plastic, or substances that have no name. Some are jagged bits of interesting material or small, coinlike objects (such as highly decorative buttons from a machine), while others are properly minted and stamped, with writing and images.