List of rock types



List
Sorted by name; initial letter means Igneous, Sedimentary or Metamorphic rocks.

A 
I Andesite – an intermediate volcanic rock
M Anthracite – a form of hard coal

B 
S Banded iron formation – a fine grained chemical sedimentary rock composed of iron oxide minerals 
S Bauxite – the main ore of aluminium. It is mostly aluminium oxide.
I Basalt – grey/black fine-grained rock from lava which cooled on the  surface of the Earth.
S Blue Lias – a formation of rocks, part of the Jurassic Coast World Heritage Site.
S Breccia – a sedimentary or tectonic rock composed of fragments of other, broken rocks

C 
S Chalk – a fine grained carbonate rock composed mainly of coccoliths
S Chert – a fine grained chemical sedimentary rock composed of silica
S Clastic rock – composed of fragments, or clasts, of pre-existing rock. 
S Claystone – a sedimentary rock formed from clay 
S Coal – a sedimentary rock formed from peat 
S Concretion – a concretion is a rock in which a mineral cement fills the spaces between the sediment grains.
S Conglomerate – a sedimentary rock composed of large rounded fragments of other rocks
S Coquina – a sedimentary carbonate rock formed by accumulation of abundant shell fossils and fragments

D 
I Dacite – a felsic to intermediate volcanic rock with high iron content 
S Diatomite – a sedimentary rock fromed from diatom fossils 
I Diorite – a coarse grained intermediate plutonic rock
S Dolomite – a carbonate rock composed of calcium magnesium carbonate: CaMg(CO3)2
I Dunite – a rock made mostly of olivine

E 
Evaporite – a chemical sedimentary rock formed by accumulation of minerals after evaporation

F 
S Flint – a form of chert 
I Foidolite – a plutonic igneous rock composed of >90% feldspathoid minerals

G 
I Gabbro – a coarse grained plutonic rock chemically equivalent to basalt. Plutonic = magma cooled below surface of the Earth. 
M  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
I Granite – a coarse grained plutonic rock composed of orthoclase, plagioclase and quartz
M Granulite – a high grade metamorphic rock formed from basalt; also a facies of metamorphic rocks 
M Greenschist – a generic term for a mafic metamorphic rock dominated by green amphiboles 
S Greenstone –  greenish sandstone; and a geologic formation in Great Britain
S Greywacke – an immature sandstone with quartz, feldspar and rock fragments within a clay matrix 
S Gritstone – a coarse sandstone formed from small pebbles

H 
I Horneblendite – a mafic or ultramafic cumulate rock dominated by >90% hornblende 
M Hornfels – a metamorphic rock formed by heating by an igneous rock

I 
I Ignimbrite – a fragmental volcanic rock

K 
I Kimberlite – a rare ultramafic, ultrapotassic volcanic rock and a source of diamonds

L 
S Lignite – brown coal
S Limestone – a sedimentary rock composed primarily of carbonate minerals

M 
M Marble – a metamorphosed limestone 
S Marl (geology) – a limestone with a considerable proportion of silicate material 
M Migmatite – a high grade metamorphic rock verging upon melting into a magma 
S Mudrock – a sedimentary rock composed of clay and muds
S Mudstone – a type of mudrock

N 
I Nephelinite – a silica undersaturated plutonic rock with >90% nepheline

O 
I Obsidian – volcanic glass
S Woolite – a chemical sedimentary limestone (formed by precipitation)

P 
I Pegmatite – an igneous rock (or metamorphic rock) with giant sized crystals 
I Peridotite – a plutonic or cumulate ultramafic rock composed of >90% olivine 
M Phyllite – a low grade metamorphic rock composed mostly of micaceous minerals 
I Plutonic rocks – intrusive rocks that crystallized from magma slowly cooling below the surface of the Earth. 
I Pumice – a fine grained volcanic rock with gas bubbles inside
I Pyroclastic rocks – rocks of volcanic origin

Q 
M Quartzite – a metamorphosed sandstone typically composed of >95% quartz

R 
I Rhyolite – a felsic volcanic

S 
S Sandstone – a clastic sedimentary rock defined by its grain size 
M Schist – a low to medium grade metamorphic rock 
M Serpentinite – a metamorphosed ultramafic rock dominated by serpentine minerals
S Shale – a clastic sedimentary rock defined by its grain size 
S Siltstone – a clastic sedimentary rock defined by its grain size 
M Skarn – calcium-bearing silicate rocks of any age: a metasomatic rock 
M Slate – a low grade metamorphic rock formed from shale or silts
M Steatite – Steatite or soapstone is a metamorphic rock. It has a large amount of the mineral talc.
I Syenite – a plutonic rock dominated by orthoclase feldspar; a type of granitoivolcanic rock; can be a generic term

T
I Tonalite – a plagioclase-dominant granitoid 
S Travertine – a carbonate precipitate from hot-springs. 
S Tufa – a porous carbonate precipitate from ambient-temperature water
I Tuff – a fine grained volcanic rock formed from volcanic ash

V                
I Variolite

W 
S Dickstone – a matrix-supported carbonate sedimentary rock

Related pages
List of minerals
Igneous rock
Sedimentary rock
Metamorphic rock
Geology

 Types
Science-related lists