40d:Stone

Stone or rock is a naturally occuring solid aggregate of minerals. It sometimes leaves behind material after being mined or collapsing. Other types of minable tiles include soil and sand.

Stone is divided into a few key categories:

• Metal ore: stone that produces metal bars when smelted
• Rough gems: rough gems can be cut, then used to encrust objects and create windows.
• Other stone: Stone that is not an ore or a gem. 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.

This article is about DF geology and the distribution of stones, and does not contain the specific locations of metal ores or gems.

Main layer types

There are four types of stone layers (all others are soil). The type of layer is the primary indicator of what kind of ore you will find on the map, as well as a sign of volcanic activity. The types are sedimentary layers, igneous intrusive layers, igneous extrusive layers, and metamorphic layers.

The primary types of rock only occur in their own layers. (e.g. you won't find limestone in a marble layer.)

Stones forming entire layers

These types of stone occur as entire layers, containing some veins and pockets of other minerals (see below). If one of the following types of stone is present on your map, it will be listed in one of the biomes on the embark screen.

Sedimentary	Igneous intrusive	Igneous extrusive	Metamorphic
# ● Sandstone % ● Siltstone ≈ ● Mudstone . ● Shale , ● Claystone # ● Rock salt ▓ ● Limestone ∞ ● Conglomerate ` ● Dolomite ▓ ● Flint = ● Chert ░ ● Chalk	▓ ● Granite ░ ● Diorite ▒ ● Gabbro	, ● Rhyolite # ● Basalt ∞ ● Andesite . ● Felsite ▒ ● Obsidian	- ● Quartzite % ● Slate - ● Phyllite ` ● Schist = ● Gneiss ▓ ● Marble

Other Stone

Stones found on this table will occur as pockets and veins inside their respective stone layers (see above). When your miners encounter one of them, the game will pause and 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.

Non-layer stone occurs in these forms:

• Large cluster - An oval that occupies nearly half of a 48x48 block, area-wise. Only one appears per block. These average 750 stones each.
• Vein - A sinuous line of the material crosses the block. These average 100 stones each.
• Small cluster - A sprinkle of 1 to 9 adjacent tiles. Multiple small clusters of different materials may be in the same block. These average 5 stones each and do not span more than three tiles in each direction.

The following table does not contain ores and gems. The types of stone listed here that do not link to their own article are generic.^{v0.28.181.40d}

Icons	Name	Found in	Found how
^ ●	Alabaster	Gypsum	Small clusters
` ●	Alunite	All Igneous extrusive, Kaolinite	Large clusters
v ●	Anhydrite	Gypsum, Satinspar, Alabaster, Selenite	Single
+ ●	Bauxite	All Sedimentary	Large clusters
☼ ☼	Bituminous coal	All Sedimentary	Veins
` ●	Borax	Gypsum, Rock_Salt	Small clusters
% ●	Brimstone	All Igneous extrusive, Gypsum	Small clusters
" ●	Calcite	Limestone, Marble	Small clusters
= ●	Chromite	Olivine	Veins
£ *	Cinnabar	All Igneous extrusive, Shale, Quartzite	Veins
£ *	Cobaltite	All Igneous All Metamorphic	Veins
- ●	Cryolite	Granite	Small clusters
o ●	Graphite	Gneiss, Quartzite, Marble, Schist	Small clusters
# ●	Gypsum	All Sedimentary	Large clusters
" ●	Hornblende	All Igneous, All Metamorphic	Small clusters
. ●	Ilmenite	Gabbro	Small clusters
░ ●	Jet	All Sedimentary	Large clusters
= ●	Kaolinite	All Sedimentary	Large clusters
% ●	Kimberlite	Gabbro	Veins
* ●	Lignite	All Sedimentary	Veins
% ●	Marcasite	Kaolinite	Small clusters
v ●	Mica	All Metamorphic, Granite	Large clusters
% ●	Microcline	All Stone	Large clusters
% ●	Olivine	Gabbro	Large clusters
- ●	Orpiment	All Igneous extrusive	Small clusters
% ●	Orthoclase	All Igneous intrusive, All Metamorphic	Large clusters
, ●	Periclase	Marble	Small clusters
% ●	Petrified wood	All Sedimentary	Small clusters
* ●	Pitchblende	Granite	Small clusters
Θ ●	Puddingstone	Conglomerate	Large clusters
% ●	Pyrolusite	All Igneous	Small clusters
% ●	Realgar	All Igneous extrusive	Small clusters
` ●	Rutile	All Metamorphic, Granite	Small clusters
x ●	Saltpeter	All Sedimentary	Small clusters
- ●	Satinspar	Gypsum	Small clusters
; ●	Selenite	Gypsum	Small clusters
≈ ●	Serpentine	Olivine	Small clusters
% ●	Stibnite	All Igneous extrusive	Small clusters
= ●	Sylvite	Rock salt	Large clusters
| ●	Talc	Dolomite	Large clusters

DF Geology and real-world Geology

The geology and stones of Dwarf Fortress are based 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.