In StarCraft II, the resource harvested from gas geysers by all three races is vespene gas.
Vespene gas is one of the two primary standard resources in StarCraft II, alongside minerals. Players construct race-specific structures on vespene geysers to collect it: Refineries for Terrans, Assimilators for Protoss, and Extractors for Zerg. Gas is commonly needed for advanced units, technologies, and upgrades.
Minerals are the other standard multiplayer resource, but they are gathered from mineral fields rather than gas geysers. Terrazine is a special resource used in particular campaign missions and is not the ordinary resource collected from standard geysers. Umoja gas is not the standard name for a StarCraft II resource.
Managing gas is important because many powerful units require a large gas investment. A player with abundant minerals but insufficient vespene gas may be unable to produce advanced technology, while taking additional geysers can accelerate tech development at the cost of workers and expansion resources.