List of rock types

From MedBib.com - Medicine & Nature

This page is intended as a list of all unique rock types as recognised by petrologists. Names of non-rock types and archaic rock types are given as appendices.

Contents

Igneous

A sample of andesite (dark groundmass) with amygdaloidal vesicules filled with zeolite. Diameter of view is 8 cm.
Andesite - an Intermediate volcanic rock
Anorthosite - an igneous ultramafic rock composed predominantly of plagioclase
Aplite - a very fine grained intrusive igneous rock
Basalt - a volcanic rock of mafic composition
Adakite - a class of basaltic rocks containing relatively small amounts of the trace elements yttrium and ytterbium
Hawaiite - a class of basalts formed from Ocean Island (hot spot) magmatism
Icelandite
Picrite
Basanite - a volcanic rock of mafic composition; essentially a silica undersaturated basalt
Boninite - a high-magnesian basalt dominated by pyroxene
Carbonatite - a rare igneous rock composed of >50% carbonate minerals
Charnockite - a rare type of granite containing pyroxene
Enderbite - a variety of charnockite
Dacite - a felsic to intermediate volcanic rock with high iron content
Diabase or dolerite - an intrusive mafic rock forming dykes or sills
Diorite - a coarse grained intermediate plutonic rock composed of plagioclase, pyroxene and/or amphibole
Dunite - an ultramafic cumulate rock composed of olivine and accessories
Essexite - a silica undersaturated mafic plutonic rock (essentially a foid-bearing gabbro)
Foidolite - a plutonic igneous rock composed of >90% feldspathoid minerals
Gabbro - a coarse grained plutonic rock composed of pyroxene and plagioclase basically equivalent to basalt
Granite - a coarse grained plutonic rock composed of orthoclase, plagioclase and quartz
Granodiorite - a granitic plutonic rock with plagioclase > orthoclase
Granophyre - a subvolcanic intrusive rock of granitic composition
Harzburgite - a variety of peridotite; an ultramafic cumulate rock
Hornblendite - a mafic or ultramafic cumulate rock dominated by >90% hornblende
Hyaloclastite - a volcanic rock composed primarily of glasses and glassy tuff
Icelandite - a volcanic rock
Ignimbrite - a fragmental volcanic rock
Ijolite - a very rare silica-undersaturated plutonic rock
Limey shale overlaid by limestone. Cumberland Plateau, Tennessee
Kimberlite - a rare ultramafic, ultrapotassic volcanic rock and a source of diamonds
Komatiite - an ancient ultramafic volcanic rock
Lamproite - an ultrapotassic volcanic rock
Lamprophyre - an ultramafic, ultrapotassic intrusive rock dominated by mafic phenocrysts in a feldspar groundmass
Latite - a silica undersaturated form of andesite
Lherzolite - an ultramafic rock, essentially a peridotite
Monzogranite - a silica undersaturated granite with <5% normative quartz
Monzonite - a plutonic rock with <5% normative quartz
Nepheline syenite - a silica undersaturated plutonic rock with nepheline replacing orthoclase
Nephelinite - a silica undersaturated plutonic rock with >90% nepheline
Norite - a hypersthene bearing gabbro
Obsidian - a type of volcanic glass
Pegmatite - an igneous rock (or metamorphic rock) with giant sized crystals
Peridotite - a plutonic or cumulate ultramafic rock composed of >90% olivine
Phonolite - a silica undersaturated volcanic rock; essentially similar to nepheline syenite
Picrite - an olivine-bearing basalt
Quartzite
Porphyry - a rock, usually granitic, with a porphyritic texture
Pseudotachylite - a glass formed by melting within a fault via friction
Pumice - a fine grained, extremely vesicular volcanic rock
Pyroxenite - a coarse grained plutonic rock composed of >90% pyroxene
Quartz diorite - a diorite with >5% modal quartz
Quartz monzonite - an intermediate plutonic rock, essentially a monzonite with 5-10% modal quartz
Rhyodacite - a felsic volcanic rock which is intermediate between a rhyolite and a dacite
Rhyolite - a felsic volcanic rock
Comendite - a peralkaline rhyolite
Pantellerite - an alkaline rhyolite-rhyodacite with amphibole phenocrysts
Scoria - an extremely vesicular mafic volcanic rock
Sovite - a coarse grained carbonatite rock
Syenite - a plutonic rock dominated by orthoclase feldspar; a type of granitoid
Tachylyte - essentially a basaltic glass
Tephrite - a silica undersaturated volcanic rock; can be a generic term
Tonalite - a plagioclase-dominant granitoid
Trachyandesite - an alkaline intermediate volcanic rock
Benmoreite - sodic trachyandesite
Basaltic trachyandesite
Mugearite - sodic basaltic trachyandesite
Shoshonite - potassic basaltic trachyandesite
Trachyte - a silica undersaturated volcanic rock; essentially a feldspathoid-bearing rhyolite
Troctolite - a plutonic ultramafic rock containing olivine, pyroxene and plagioclase
Trondhjemite - a form of tonalite where plagioclase-group feldspar is oligoclase
Tuff - a fine grained volcanic rock formed from volcanic ash
Websterite - a type of pyroxenite, composed of clinoproxene and orthopyroxene
Wehrlite - an ultramafic plutonic or cumulate rock, a type of peridotite, composed of olivine and clinopyroxene

Sedimentary

Anthracite - a type of coal
Argillite - a sedimentary rock composed primarily of clay-sized particles
Arkose - a sedimentary rock similar to sandstone
Banded iron formation - a fine grained chemical sedimentary rock composed of iron oxide minerals
Breccia - a sedimentary or tectonic rock composed of fragments of other, broken rocks
Bituminous coal seam in West Virginia
Cataclasite - a rock formed by faulting
Chalk - a sedimentary rock composed primarily of coccolith fossils
Chert - a fine grained chemical sedimentary rock composed of silica
Claystone - a sedimentary rock formed from clay
Coal - a sedimentary rock formed from organic matter
Conglomerate - a sedimentary rock composed of large rounded fragments of other rocks
Diamictite - a poorly sorted conglomerate
Coquina - a sedimentary carbonate rock formed by accumulation of abundant shell fossils and fragments
Dolomite crystals from Touissite, Morocco
Diatomite - a sedimentary rock fromed from diatom fossils
Dolomite or dolostone - a carbonate rock composed of the mineral dolomite +/- calcite
Evaporite - a chemical sedimentary rock formed by accumulation of minerals after evaporation
Flint - a form of chert
Greywacke - an immature sandstone with quartz, feldspar and rock fragments within a clay matrix
Gritstone - essentially a coarse sandstone formed from small pebbles
Itacolumite - porous, yellow sandstone
Jaspillite - an iron-rich chemical sedimentary rock similar to chert or banded iron formation
Lignite - a sedimentary rock composed of organic material; otherwise known as Brown Coal
Limestone - a sedimentary rock composed primarily of carbonate minerals
Marl - a limestone with a considerable proportion of silicate material
Mudstone - a sedimentary rock composed of clay and muds
Oil shale - a sedimentary rock composed dominantly of organic material
Oolite - a chemical sedimentary limestone
Sandstone - a clastic sedimentary rock defined by its grain size
Shale - a clastic sedimentary rock defined by its grain size
Siltstone - a clastic sedimentary rock defined by its grain size
Turbidite (Gorgoglione Flysch), Miocene, South Italy
Turbidite - a particular sequence of sedimentary rocks which form within the deep ocean environment
Wackestone - a matrix-supported carbonate sedimentary rock

Metamorphic

Amphibolite - a metamorphic rock composed primarily of amphibole
Epidiorite
Blueschist - a metamorphic rock composed of sodic amphiboles with a distinct blue colour
Phyllite
Banded gneiss with a dike of granite orthogneiss
Eclogite - an ultra-high grade metamorphosed basalt or gabbro; also a facies of metamorphic rocks
Gneiss - a coarse grained metamorphic rock
Gossan - the product of the weathering of a sulfide rock or ore body
Granulite - a high grade metamorphic rock formed from basalt; also a facies of metamorphic rocks
Greenschist - a generic term for a mafic metamorphic rock dominated by green amphiboles
Greenstone
Hornfels - a metamorphic rock formed by heating by an igneous rock
Marble
Marble - a metamorphosed limestone
Migmatite - a high grade metamorphic rock verging upon melting into a magma
Mylonite - a metamorphic rock formed by shearing
Pelite - a metamorphic rock with a protolith of clay-rich (siltstone) sedimentary rock
Phyllite - a low grade metamorphic rock composed mostly of micaceous minerals
Psammite - a metamorphic rock with a protolith of quartz-rich (sandstone) sedimentary rock
Quartzite - a metamorphosed sandstone typically composed of >95% quartz
Manhattan Schist, from Southeastern New York
Schist - a low to medium grade metamorphic rock
Serpentinite - a metamorphosed ultramafic rock dominated by serpentine minerals
Skarn - a metasomatic rock
Slate
Slate - a low grade metamorphic rock formed from shale or silts
Suevite - a rock formed by partial melting during a meteorite impact
Talc carbonate - a metamorphosed ultramafic rock with talc as an essential constituent; similar to a serpentinite
Soapstone - essentially a talc schist

Specific Varieties of Rocks

The following terms are used to describe rocks which are not petrographically or genetically distinct, but are defined according to various other criteria; most are specific classes of other rocks, or altered versions of existing rocks. Some archaic and vernacular terms for rocks are also included.

Adamellite - a variety of quartz monzonite
Appinite - a group of varieties of lamprophyre, mostly rich in hornblende
Aphanite - an aphanitic felsic volcanic rock which confounds identification via optical means
Borolanite - a variety of nepheline syenite from Loch Borralan, Scotland
Blue Granite - essentially larvikite, a monzonite
Epidosite - a type of metasomatite; essentially altered basalt
Felsite - an aphanitic felsic volcanic rock which confounds identification via optical means
Flint - typically a form of chert, jasper, or tuff
Ganister - a Cornish term for a palaeosol formed on sandstone
Ijolite - a silica-undersaturated plutonic rock associated with nepheline syenites
Jadeitite - a very rare rock formed by concentration of jadeite pyroxene; a form of serpentinite
Jasperoid - a hematite-silica metasomatite analogous to a skarn
Kenyte - a variety of phonolite, first found on Mount Kenya
Vogesite - a variety of lamprophyre
Larvikite - a variety of monzonite with microperthitic ternary feldspars from Larvik, Norway
Litchfieldite - a metamorphosed nepheline syenite occurrence near Litchfield, Maine
Luxullianite - a tourmaline-bearing granite with a peculiar texture, occurring at Luxulyan, Cornwall, England
Mangerite - a hypersthene-bearing monzonite
Minette - a variety of lamprophyre
Novaculite - a chert formation found in Oklahoma, Arkansas and Texas
Pyrolite - a chemical analogue considered to theoretically represent the earth's upper mantle
Rapakivi granite - a granite which exhibits the peculiar rapakivi texture
Rhomb porphyry - a type of latite with euhedral rhombic phenocrysts of feldspar
Shonkinite - an archaic and informal term used to describe melitilic and kalsititic rocks; often used today
Taconite - a term for banded iron formation primarily used in the United States of America
Teschenite - essentially a silica undersaturated, analcime bearing gabbro
Theralite - essentially a nepheline gabbro
Variolite - devitrified glass

See also

External links

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