|This article is about an older version of DF.|
Magma is a red-hot fluid that wells up from deep within the earth - but not so deep that it cannot be found by dwarves. Magma that is above the ground is called Lava but is still the same exact substance. Magma is very fun.
Magma serves as an energy source, powering magma smelters, magma forges, magma glass furnaces, and magma kilns. Magma is extremely hot which can lead to even more fun. In the current version magma seems a bit slower to burn things. Workers that dig into a magma reservoir are not instantly killed as the magma touches them and can often scramble to safetyVerify as long as they are not fully immersed in 7/7 magma. It's worth noting that magma never seems to blink with flow now either.
The list of materials that are magma-safe has been expanded considerably in this version. Magma never cools, but can evaporate if left at a depth of 1/7 for long enough. When magma is mixed with water it forms obsidian. Note that magma located above semi-molten rock will be listed as a Magma Flow and cannot be cooled into Obsidian.
Without screw pumps to impart pressure, magma flows rather slowly (though no more slowly than unpressurized water). A pipe to bring magma across the full map can take as much as a year to fill. This, combined with the fact that it will evaporate, can make filling a reservior difficult and tedious. As a rule of thumb, the area coming out of a 1-wide-pipe shouldn't be more than three squares wide and 20 squares long, or else it will evaporate as fast as you fill it.
Bringing Magma Up
Magma can be brought to the surface by two different methods:pump stacks, and magma pistons. Pump stacks are conceptually the simplest, but require an enormous amount of in-game time to make. Magma pistons tend to be faster to make, but require more time to understand how to build them.
Pumping magma up from the magma sea via a conventional pump stack is a lot of work, requiring dozens of pumps and significant amounts of power. Making all of the pumps magma safe also requires a lot of precious materials like steel or glass.
Magma pistons are another way to move magma near the surface. Magma pistons require less time and fewer precious materials to construct than pump stacks. However, magma pistons are a bit more complicated than pump stacks, so it takes more time to understand how to operate and build them.
Although the name suggests them as pools, they are actually pipes (Unknown why Toady changed the name). They can be found underground, however they rarely reach the upper z-levels (40+). Most end just a few z-levels above the magma sea, though some may span more than 100 z-levels. Magma pools seem to be always connected to a magma sea, and the sea and pipe can occasionally reach up to the same level, making them hard to separate. However, magma pools can be identified by the obsidian walls which surround them. Magma pools will slowly refill themselves, giving the player an infinite source of magma.
Volcanoes are magma pools that extend all the way to the surface. Volcanoes are an endless source of magma as they will always refill themselves.
Properties of magma
Magma behaves the same way as water with the exception of not being affected by pressure (except when being moved by a screw pump) and apparently not showing flow. Magma will turn into obsidian1 if it touches water. In the game, magma's temperature is 12,000 (2,032°F, or about 1,111°C). See the list of magma-safe materials for more information on what can (or cannot) be safely submerged in magma.
Tiles directly adjacent to magma will be heated to a temperature of 10,075 (107°F, or about 42°C), causing revealed unmined tiles to flash with
☼ when placing digging designations and causing unrevealed mining-designated tiles to cancel their designation (with a "warm stone" warning) once they are revealed.
1 - specifically, one of the inorganic materials having the [LAVA] tag, selected randomly per biome during worldgen.
Dangers of magma
Magma is not immediately fatal when first touched. It is dangerous to stand in magma, but dwarves will generally only suffer minor burns when running from a flow. Most creatures can survive standing on even a completely filled magma tile for a single step, but any more and they will likely die. This may be intentional