40d:Magma

Magma serves as an energy source, powering magma forges, magma glass furnaces and magma smelters. It is extremely dangerous.

Finding magma

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 that reaches all the way to the surface is 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). 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.

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, or even all three - 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 the only way to identify them is to scroll past hundreds of local maps while keeping an eye out 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 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 slowly replenish their supply of magma^{v0.27.176.38a}. Other sources of magma do not^[Verify], limiting the use of magma for traps, moats, etc on maps lacking a volcano.

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.

• Workshops that come in contact with the magma (such as forges) need not be built of steel to function.

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

• Bridges that cross magma must be constructed of steel, as their supports are theoretically submerged in the magma.

• Most items that can have mechanisms attached to them must be made of steel or bauxite to function in magma. This includes Floodgates and Screw Pumps^[Verify].

• Stone mechanisms attached to a construction will melt in magma unless made of bauxite, 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.^{v0.27.176.38a} 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 chance of using a prolonged contact between the two to create a steam trap.
• Rocks: Rocks left over from mining will melt if magma covers them.
• Speed: Magma moves relatively slowly. While it is 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.