Polarity scanner

Invidium

A polarity scanner illuminates invidium

A polarity scanner was a piece of technology carried aboard Starfleet vessels. When scanning, it produced a series of different colored beams, with the purple beam used to identify invidium.

In 2366, Geordi La Forge used a polarity scanner to illuminate invidium from a Mikulak container. (TNG: "Hollow Pursuits")