Fuel Gel

From Wikitroid, the Metroid wiki

Fuel Gel is the liquid in Metroid Prime 3: Corruption used primarily as fuel for ships including Samus' own. It is volatile and will ignite easily, and can be frozen by low tempetures. According to a creature log, it can give off toxic vapor. The Federation has control over distribution of the substance and proceeds from Bryyonian gel sales go directly to the Federation military forces protecting that sector of space. Space Pirates are said to desire the liquid so the Federation works to increase anti-piracy defenses. In some qualities, it's similar to Phazon, although not as powerful in energy output. It can be frozen and can damage the shielding in Samus' powersuit if she's in direct contact with the liquid gel. However once she gets the Hazard Suit it can't harm her. It is extremely rare, except on Bryyo, where there are lakes and rivers of fuel gel in the Bryyo Fire, which is the main source of the substance.

Interestingly, several different species have evolved not only to live in, but thrive on fuel gel, including Gel Rays, Gel Puffers, and Gelbugs.

It is likely that this source of fuel replaced Afloraltite.