40d:Magma

Magma is red-hot molten rock present in volcanoes, as well as magma pools and magma pipes. It serves as an energy source, powering magma forges, magma glass furnaces and magma smelters. It is extremely dangerous.

Magma sources

While in previous versions of Dwarf Fortress, every map was guaranteed to have magma, since v0.27.169.32a magma is now a feature of terrain and may or may not be present.

Magma occurs in three different features; Magma pools, Magma Pipes, and Volcanoes.

• A Magma Pool is a reservoir of magma that occupies only a few Z-Levels in the mountain, without reaching the surface. Magma Pools can be very small, and may have few suitable locations for buildings that rely on magma. Magma in these pools is limited, and pools will not refill with magma once emptied.

• A Magma Pipe starts at the lowest z-level of the map from an magma (or lava) flow and extend in a pipe shape upwards, sometimes reaching the surface but often not. Magma Pipes gradually refill with magma.

• A Volcano is similar to a magma pipe, but it has the advantage of being a geographical feature that is visible on the location screen. This means that it is a lot easier to find. However, it IS actually possible for a volcano that shows up on the "local" and region screen in the starting location chooser to be entirely underground - Although you could see it in the starting location chooser, it would not be visible from the surface once your dwarves have arrived at the fort's site.

Finding magma

Volcanos are visible on the "local" screen in the starting location chooser. It is represented as a red ≈ mark (a double tilde) - essentially it looks like red water. Note that red ≈ marks in the "region" screen mean something different entirely (e.g. red sand). If you are using a certain utility, you can also see magma pools and magma pipes on the local screen in the embark menu. After you have embarked for a place that has a volcano, and once your dwarves have arrived at their target destination, you should see a large red pool of lava on your map. If you don't, you should expect your volcano to be somewhere underground. You then have to use exploratory mining to find it.

While picking a starting location, the easiest place to look for magma is on or near a volcano (a red ^ mark in the "region" screen). There are often volcanic islands (easy to find, since they are the sole land in the middle of oceans), but since sea travel is not yet implemented, trade with other races may not be possible on such islands. Instead, find a volcano on land, and (optionally) start looking for a vent in nearby squares. "Nearby squares" can mean anything from literally on top of the volcano, to adjacent, to quite a long distance away indeed. The placement of magma seems to be related to the distance from volcanoes, but is still essentially random.

Magma vents occur exclusively in world map tiles that are primarily igneous extrusive. That is to say, if you select an entire tile on the embarkation screen and press F1 to highlight the most common terrain, the tile will only have magma if the top stone is dark gray, signifying igneous extrusive rock. Magma does not necessarily form in this geological zone/biome, rather anywhere in the tile. Even if magma is not evident on the surface, it's almost certain to be underground somewhere, though the chances of finding it without reveal.exe are still slim.

Much harder than simply finding a magma vent is finding a magma vent that is also near suitable terrain for building. Depending on your requirements - you may be looking for a source of running water, or a mountain for minerals, or a healthy tree population, a layer of flux for steel production or even all four - suitable building sites can be extremely scarce.

Since volcanoes show up on the region finder, and magma vents do not, you may find it easier to simply check all volcanoes on a map for suitability, and generate a new world if none are suitable, rather than scouring tile after tile for magma vents.

If you're willing to search exhaustively, you might want to consider finding magma vents that are not near volcanoes at all. Very occasionally, magma will be visible in the middle of forests, plains, or other terrain nowhere near a volcano or even mountains. There is no way to spot these on the region map, so you have to review the local maps. This can be done from DF, but since it involves a lot of scrolling and is very tedious, you can try exporting the local map of the world which can be much more quickly searched for the distinctive red ≈ symbol.

You can also occasionally find magma that does not extend all the way to the surface, and therefore is not visible on the local map. These are in fact much more numerous than surface-visible magma vents; however, they are almost impossible to find without cheating via one of the utilities like "reveal.exe", since unlike proper magma vents these smaller deposits must be almost literally mined into to see (you will get a warning about "warm stone" before you actually breach the deposit). These smaller magma deposits appear in the same places as normal magma vents - near volcanoes, or, failing that, near other known magma.

Using magma

On a map with a magma vent, the magma will be clearly visible from every level ground and below, unless the map is in a Freezing area. In Freezing areas, the top few levels of the vent will have cooled to form an obsidian "cap". This should still be readily recognizable however, as it will comprise a circular area. The minerals directly adjacent to the magma vent will also be immediately visible, even at the lowest level of the map, which can give some hints about where to prospect for ores.

The vent has a similar, circular shape on each level. However, it is not identical from one level to the next; some levels will have a larger or somewhat misshapen circle of magma.

The primary use for magma is to power magma smelters, magma glass furnaces and magma forges. (There are other uses, including defense, obsidian production, and possibly even garbage disposal.) To build forges, etc. on magma, at least one of the external eight squares must be above a square of magma.

This can be done most easily by simply building on ground level. The magma is visible from ground level but is actually contained one level below ground level, just like any ground-level water source.

To build underground, you will need to dig at least one tile of a channel above the location you wish to build the smelter or forge. Underneath this channel there must be magma, either directly from the vent or channeled from the vent. You can simply build a tunnel straight into the magma, or use channels to tap into the magma on the level below safely - this latter is easier if there is more magma on the lower level than the level on which you wish to build. Tapping into magma directly is quite safe, provided that you are prepared for it. Magma is much slower than water, and can be stopped by a simple floodgate.

Volcanoes and magma tubes slowly replenish their supply of magma.

Magma compared to water

Magma is a chunky liquid. As such, it acts like water in certain circumstances, but acts differently in others.

Similarities

• Magma fills a tile and has seven possible depths.

• Magma flows outward and downward to expand into clear space.

• Screw pumps work in magma.

• Floodgates and pressure plates work in magma.

• Constructed walls of all kinds safely contain magma.

• Objects thrown into magma sink to the bottom.

• Magma that is only 1 deep "evaporates" over time.

Differences

• Magma is extremely hot, and capable of melting objects and constructions made of most materials (see Magma vs. Built Objects) and thus destroying them.

• Magma is never pressurized, it seeps out of holes slower than water and slow enough for any dwarves to outrun, unless they are the ones digging into it.

• Magma flows up from a direct vertical line from the bottom of a Magma Pipe only. Otherwise, its level may rise only by dripping more magma from above, and new magma may only distribute itself by moving down or to the sides, but never up.

• Magma reacts violently with water, releasing steam and, depending on the amount of magma, leaving behind tiles of solid obsidian which can be mined, smoothed or engraved like any natural tile.

• Magma is not a water source. Dwarves can't drink it or supply it to their wounded.

Magma vs. Built Objects

Some objects that come in contact with magma will function fine, no matter what their material. Others will melt or cease to work properly unless they're made of magma-safe materials.

• Workshops that are powered by magma need not be built of magma-safe materials to function.

• Constructed walls of any material, even those that are not "Magma-safe", will hold magma in without issues.

• Like walls, doors can also be built out of any material and still hold back lava as long as it's in the "closed" position. It may be wise to make sure hallways/rooms close to an engineering project involving magma have plenty of doors, just in case you have a little too much fun when you forget to build that last floodgate.

• Bridges that are built over magma may be constructed of any material. However, bridges that are submerged in magma must be constructed of a magma-safe material.

• Most machines must be made of magma-safe materials to function for more than a few minutes in magma. This includes floodgates and screw pumps. Unsafe materials will function for a while, but then burn away.

• Stone mechanisms attached to a construction will melt in magma unless made of bauxite or raw adamantine, even if the construction itself is made of steel. In addition, if the mechanisms melt off of a floodgate, the floodgate will cease to be "constructed" and become an unplaced item again.^{v0.27.176.38c} At this point, the magma will flow over it freely.

Temperature settings

Magma is almost harmless if temperature is disabled in the Dwarf Fortress init file. It can still trap and suffocate or simply starve your dwarves in some situations. It will not melt bridges, etc. constructed of non-magma-proof materials.

Magma reactions

• Water: If magma happens to contact water it produces some steam and obsidian. This means there is no longer any chance of using a prolonged contact between the two to create a steam trap, though steam is also likely now not harmful. For those of you who aren't veteran dwarves, in the old 2D version, steam was deadly.
• Brooks: If magma comes in contact with a brook, it will not produce steam, but will turn the water tile below the brook to obsidian, and give the brook tile the appearance of a dried-up brook.
• Rocks: Rocks left over from mining will melt if magma covers them.
• Speed: Magma moves relatively slowly. While it is nearly impossible to try to seal off water let loose, magma is slow enough for your dwarves to build a floodgate or door, or even wall off the flooding area, if you happen to let magma loose by mistake.
• Pressure: Magma does not transmit pressure.

Observation. I have witnessed Magma "blurp" up through a channel, while working with a Volcano. In this particular case, a floor built in the volcano, 1 z level down. (This level was created by dropping water into the volcano from overhead, create a obsidian layer.)