40d:Stone

Stone or rock is a naturally occuring solid aggregate of minerals. It sometimes leaves behind boulders after being mined (the drop rate is dependant on the skill of the miner). Other types of minable tiles include soil and sand.

Stone is divided into three key categories:

• Metal ore: stone that produces metal bars when smelted
• Raw gems
• Economic stone: coal and stone that is used as a flux, or has other desirable features
• Other stone: stone that is only used for items and structures and has no special features other than color

Layers

There are four types of stone layers. 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. You will also find layers of soil, but these rarely contain much ore.

The primary types of rocks only occur in their own layers. You won't find limestone in a marble layer.

Stone occuring as layers

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

Stone found on this table will occur inside their respective stone layers. When your miners encounter one of them, the game will pause and you will recieve an announcement; even for the ones that have no use other than to build constructions of unusual colors.

Stone name	Found in	Found how	Icons
Alabaster	Gypsum	Small clusters	^
Alunite	All Igneous extrusive, Kaolinite	Large clusters	`
Anhydrite	Gypsum, Satinspar, Alabaster, Selenite	Single	v
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	-
Graphite	Gneiss, Quartzite, Marble, Schist	Small clusters	o
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	%
Mica	All Metamorphic, Granite	Large clusters	v
Microcline	All 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	*
Puddingstone	Conglomerate	Large clusters	Θ
Pyrolusite	All Igneous	Small clusters	%
Realgar	All Igneous extrusive	Small clusters	%
Rutile	All Metamorphic, Granite	Small clusters	`
Saltpeter	All Sedimentary	Small clusters	x
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	|

Stone in real life

The geology and stone of Dwarf Fortress is based on real-world geology and mineralogy. To understand the terms used here, you may want to crack open a geology textbook. If you don't happen to have one close by, the Wikipedia articles for geology, mineralogy, or the terms in question might help.