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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
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
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
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
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
W
- S Dickstone – a matrix-supported carbonate sedimentary rock