List of rock types

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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

List Of Rock Types Media

• 

  A sample of andesite (dark groundmass) with amygdaloidal vesicles filled with zeolite. Diameter of view is 8 cm.

• 

  Bituminous coal seam in West Virginia

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  Limey shale overlaid by limestone. Cumberland Plateau, Tennessee

• 

  Dolomite crystals from Touissite, Morocco

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  Turbidite (Gorgoglione Flysch), Miocene, South Italy

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  PhylliteUSGOV

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  Banded gneiss with a dike of granite orthogneiss

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  MarbleUSGOV

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  Quartzitejpg

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  Manhattan Schist, from Southeastern New York

Related pages

• List of minerals
• Igneous rock
• Sedimentary rock
• Metamorphic rock
• Geology