Tylium (RDM)
Tylium is the material used to fuel the propulsion systems of Colonial and Cylon craft. Three forms are known of: tylium ore, refined tylium precursor, and refined tylium (the fuel itself).
Typically, tylium ore is mined from asteroids (The Hand of God) and is apparently not found on the Twelve Colonies natively. Large tylium ore deposits can keep fleets fueled for years.
Tylium ore is rendered inert and unusable when exposed to nuclear radiation. It seems extremely easy to detonate, requiring only the heat and pressure generated by a conventional warhead exploding nearby. Refined tylium precursor is easier to trigger than the fuel itself. Tylium's detonation results in no radioactive fallout (The Hand of God).
Note
The official series web page on the Sci-Fi Channel web site shows the spelling of the mineral as "tyllium" in the description of the Mining Ship on the Ships page. Battlestar Wiki currently accepts the spelling of the mineral in either format.