Tylium (RDM)
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Tylium Ore is the mineral from which fuel used in propulsion systems of Colonial and Cylon craft is refined from.
Typically, tylium ore is mined from asteroids (Hand of God) and is apparently not found on the 12 Colonies natively. Large tylium ore deposits can keep fleets fueled for years.
Additionally, tylium ore is rendered inert when exposed to nuclear radiation/fallout. (Hand of God)