Boridium

Boridium was a substance used in Romulan and Federation technology.

History
Boridium power cells were used in the construction of Romulan mines which the encountered in 2152. In 2154, the Romulans utilized a similar technology in the power matrices of their drone ships, although they were smaller and much more sophisticated. 

The Hill People of the Argus River region on Rigel IV used boridium for the blades of a kind of knife they produced; one such weapon was involved in a series of murders on Argelius II in 2267. 

The Romulan prison camp on Carraya IV tracked prisoners' locations by using the energy signatures of boridium pellets implanted beneath the skin. 

In 2369, boridium was used in exocomps as a power network.