|This article is about the current version of DF.|
- (This article is about DF geology and the distribution of stones, and does not contain the specific locations of ores or gems. For that, as well a general introduction to the new player, see The Non-Dwarf's Guide to Rock)
- (For a list of stone sorted by tile see Tilesets#Stones)
An unmined rock or stone tile is a naturally occurring solid aggregate of minerals. Mining a rock tile leaves behind a loose stone (or just "stone") roughly 25% of the time. Other types of minable tiles include soil, sand, and clay; these tiles do not produce loose stones when mined.
Loose stones are divided into a few key categories:
- Ore: stones that produces metal bars when smelted
- Rough gems: rough gems can be cut, then used to encrust objects and create windows.
- Other stone: all other stones. Few of these have a use outside of items and structures. (Obsidian is one exception).
Economic stones are types of stone that can be reserved for a special purpose. For ores, this is smelting and for fluxes, this is steel production. Bituminous coal and lignite can be reserved for making coke.
Having created loose stone, many times you'll want to get rid of it or at least move it someplace else. See stone management for advice.
If you are having the opposite problem, and find yourself running out of stone, try making stone blocks.
Main layer types
There are four types of stone layers (plus soil, which is not stone). The type of layer is the primary indicator of what kind of ores you are likely to find on the map, as well as a sign of volcanic activity.
Stones forming entire layers
These types of stone occur as entire layers, containing some veins and pockets of other minerals (see below).
|Sedimentary||Igneous intrusive||Igneous extrusive||Metamorphic|
Stones found on this table will occur as pockets and veins inside their respective stone layers (see above). When your miners newly encounter one of them you will receive an announcement, even for the ones that have no use other than to build constructions of unusual colors. Note that the veins or clusters can spread into other layers, and may cause some layers to contain stones they usually wouldn't. A few of these stones, such as Olivine, have other, more interesting minerals appear inside them.
Non-layer stone formations occur in one of three shapes: large clusters, veins, and small clusters. (See Veins & Clusters for full info.)
- (L) - occurs in large clusters
- (V) - occurs in veins
- (S) - occurs in small clusters
- (1) - occurs in individual tiles
For those concerned with aesthetics and wanting to know which stones are available in each color.
|"Stone" in other Languages
DF Geology and Geology in Real Life
The geology and stones of Dwarf Fortress are based (to some extent) on real-world geology and mineralogy. To understand the terms used here, you may want to crack open a geology textbook (a high school one should suffice). If you don't happen to have one close by, the Wikipedia articles for geology, mineralogy, or the terms in question might help. Below is a very brief introduction tailored for DF gamers, with links to the relevant game-specific pages.
In geological terminology, a rock or stone is basically a composite of minerals. Minerals, the building blocks of rock, are hard inorganic materials with a definite chemical formula and a certain atomic structure. For example, the mineral quartz is composed of silicon dioxide (SiO₂) arranged in a pyramid structure. Quartz is a component mineral of rocks (stones) such as quartzite (almost entirely made of quartz) or granite (some 20~60% quartz, a bunch more of the mineral "feldspar", plus mica and some others). The distinction between minerals like mica (simple) and rocks like granite (composite) does not matter for Dwarf Fortress; just like in everyday language, they're all just "stones". Besides minerals, some rocks may include organic material; such rocks include bituminous coal (made of dead bog things) or limestone (made of the skeletons of ocean animals).
The three minerals seen in granite are also among the most common:
- Feldspar, meaning something like "field-stone", is actually a general name for an entire family of minerals, all of them based on aluminum and silicon. Their appearance varies, but they tends toward light greyish colors, and make up a lot of your typical light stone. Feldspar doesn't exist independently in the DF world; but, among the in-game stones, microcline and orthoclase are flavors of feldspar, and countless other DF stones would include feldspar in real life. A stone with a lot of feldspars and silicon is said to be felsic; granite and rhyolite are in-game examples.
- Quartz, meaning "hard", easily makes big showy crystals; it's transparent if pure, but if the SiO₂ is combined with trace amounts of other elements (often metals like iron and manganese), it can get colored pink, purple (amethyst), yellow (citrine), and so on. If bubbly with air, quartz may become milky; if irradiated, it may get smoky.
- Micas, like quartz, have silicon atoms crystalline structures. The difference is that they're organized in sheet-like, gleaming surfaces, held together by weaker bonds of other elements; this makes micas soft and flaky (the word means "grainy"). The color varies. The in-game stone mica is stated to be muscovite, which is a light variety (but the game color is dark gray, like coal; this may be a mistake). Other micas can be dark.
Other minerals that exist independently in DF include green olivine (yes, it's named after olives) and black hornblende, which is similar to dark mica but forms needlelike crystals. Dark minerals like these often include magnesium and iron (Fe); stones rich in them are then termed mafic (in contrast with "felsic"). In-game mafic stones include basalt and gabbro.
On the white side, calcite is a mineral based on calcium, the same stuff as bones. It forms crystals, and occurs in DF as an unremarkable white stone. Calcite is a main component of limestone and chalk—which in turn can become marble; it's often formed from the accumulated remains of ancient marine animals (for a memorable use of chalk stone layers in high fantasy, check out Terry Pratchett's novel The Wee Free Men and its sequels). The most well-known marine mineral is surely table salt, present in DF as rock salt. It's formed when saltwater evaporates; another evaporative mineral, or "evaporite", is gypsum, which, in DF as in real life, can be used to make plaster casts
Mica is a flaky, crumbly and sheet-like mineral. This is the lighter flavor "muscovite", present in DF.
The dark green mafic mineral olivine is a component of many basalts.
A large cluster of gypsum crystals (human for scale).
Rocks can be classified by their creation processes, which makes them settle down in distinct stone layers, and possibly in veins and clusters. DF models this too, so that it's quite relevant information for players; see the links for details.
An ore is a rock with a metal content high enough for it to be a viable source of that metal. Most metals do not occur by themselves in nature, but readily bind with minerals to form stones; e.g. zinc binds with sulfur minerals to form the rock sphalerite. To extract the metal from it, someone has to smelt the stone. A few metals may be found in pure form, like native gold and silver (but in DF, they still require smelting to be shaped into useable bars).
A gem is a mineral (or rock, or rock-like material) with intrinsic economic value for a culture, often because they're beautiful, durable, and/or rare. This depends not just on what's the mineral made of, but also on the internal layout of its atomic structure, which can dramatically alter its appearance and properties; see the article on gems for more.