Spring

Springs are single units of liquids which generate within the world, usually flowing out to accompany space. There exist three main categories of fluid springs.

Normal springs
The most familiar type of spring, these can generate as either water or lava, and generate in the sides of stone surfaces. These are commonly encountered on the sides of cliffs, as well as inside caves. Lava springs are a common source of forest fires.

Normal springs do not generate above a certain altitude.

Ceiling springs
These types of springs are exclusive to the Nether, and only generate as lava. As their name implies, they only generate on ceilings, and the liquid flows directly downwards from them. These are quite common sightings in the Nether, and the resultant lava spreading can sometimes make traversing terrain difficult.

Hidden lava
Unlike the other types of springs, these are hidden from generation. These are particularly dangerous and care must be taken when mining in the Nether, as they can be dangerous when uncovered.