![Chewable tracker](https://cdn.statically.io/img/static.wikia.nocookie.net/memoryalpha/images/f/f9/Chewable_tracker.png/revision/latest/scale-to-width-down/180?cb=20200309184551&path-prefix=en)
A viridium tracker
A viridium tracker was an isotope that, if chewed and absorbed into the bloodstream by a person, allowed them to be tracked over long distances. It could be destabilized and rendered ineffective by an injection of noranium hydride.
In 2399, Commodore Oh gave Doctor Agnes Jurati a viridium tracker after showing her the Admonition. Narek used the tracker to follow La Sirena after it left the Artifact, until Jurati neutralized it with noranium hydride. (PIC: "Nepenthe", "Broken Pieces")