List of rock types

Igneous

Adakite - a class of intermediate to felsic rocks containing low amounts of yttrium and ytterbium Andesite - an intermediate volcanic rock Alkali feldspar granite - a granitoid in which at least 90% of the total feldspar is in the form of alkali feldspar Anorthosite - a mafic intrusive igneous rock composed predominantly of plagioclase Aplite - a very fine-grained intrusive igneous rock composed of quartz and feldspar, similar composition to granite but with grains <1mm Basalt - a volcanic rock of mafic composition Basanite - a volcanic rock of mafic composition; essentially a silica-undersaturated basalt Boninite - a magnesium-rich basalt dominated by pyroxene Carbonatite - a rare igneous rock composed of >50% carbonate minerals Charnockite - a type of granite containing orthopyroxene Dacite - a felsic to intermediate volcanic rock containing hornblende and with more plagioclase than orthoclase 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 - a phaneritic ultramafic rock composed of more than 90% olivine Essexite - a silica-undersaturated mafic plutonic rock (essentially a feldspathoid-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 more plagioclase than 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 - an iron-rich, aluminium-poor andesite Ignimbrite - a fragmental volcanic rock Ijolite - a very rare silica-undersaturated plutonic rock Kimberlite - a rare ultramafic, ultrapotassic volcanic rock and a source of diamonds Komatiite - an ultramafic volcanic rock with very high magnesium content 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 of nepheline and alkali feldspar 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 crystals >1 inch, usually granitic Peridotite - a plutonic or cumulate ultramafic rock composed of olivine and pyroxene Phonolite - a silica-undersaturated volcanic rock; essentially similar to nepheline syenite Picrite - an olivine-bearing basalt Porphyry - a rock, usually granitic, with a porphyritic texture Pumice - a fine grained, 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 Quartzolite - an intrusive rock composed mostly of quartz Rhyodacite - a felsic volcanic rock which is intermediate between a rhyolite and a dacite Rhyolite - a felsic volcanic rock 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 Tonalite - a plagioclase-dominant granitoid Trachyandesite - an alkaline intermediate volcanic rock 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

Argillite - a sedimentary rock composed primarily of clay-sized particles Arkose - a sandstone with <25% feldspar crystals 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 Calcarenite - a sedimentary rock composed of > 50% detrital carbonate grains 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 Coquina - a sedimentary carbonate rock formed by accumulation of abundant shell fossils and fragments Diamictite - a lithified sedimentary deposit with a wide range of grain sizes Diatomite - sedimentary rock formed from diatom fossils Dolomite or dolostone - a carbonate rock composed of the mineral dolomite +/- calcite Evaporite - chemical sedimentary rock formed by accumulation of minerals after evaporation; varieties include rock salt (halitite) and rock gypsum Flint - a form of chert Geyserite - opaline silica deposit formed around hot springs and geysers Greywacke - a type of sandstone with quartz, feldspar and rock fragments within a clay matrix Gritstone - essentially a coarse sandstone formed from small pebbles Itacolumite - porous, yellow-orange sandstone which is flexible if cut into thin strips Jaspillite - an iron-rich chemical sedimentary rock similar to chert or banded iron formation Laterite - residual sedimentary rock formed from a parent rock under tropical conditions Lignite - sedimentary rock composed of 60%- 70% organic material; otherwise known as brown coal Limestone - composed primarily of carbonate minerals Marl - limestone with a considerable proportion of silicate material Mudstone - clastic sedimentary rock that contains a mixture of silt- and clay-sized particles Oil shale - sedimentary rock composed dominantly of organic material Oolite - chemical sedimentary limestone formed from ooids, spherical grains composed of concentric layers Sandstone - clastic sedimentary rock defined by its grain size Shale - clastic, fissile sedimentary rock defined by clay-sized particles Siltstone - clastic sedimentary rock defined by 50% or greater silt-sized particles Tillite - lithified glacial till Travertine - sedimentary rock containing calcite and iron oxides Tufa - porous limestone formed by the precipitation of carbonate minerals from ambient temperature water bodies Turbidite - particular sequence of sedimentary rocks which form within the deep ocean environment Wackestone - matrix-supported carbonate sedimentary rock.

Metamorphic

Anthracite - metamorphosed coal, between 92% - 98% organic matter Amphibolite - a metamorphic rock composed primarily of amphibole Blueschist - a metamorphic rock composed of sodic amphiboles with a distinct blue color Cataclasite - a rock formed by faulting Eclogite - an ultra-high grade metamorphosed basalt or gabbro; also a facies of metamorphic rocks Gneiss - a high grade coarse grained metamorphic rock with light and dark alternating bands Granulite - a high grade metamorphic rock formed from basalt; also a facies of metamorphic rocks Greenschist - a mafic metamorphic rock dominated by green amphiboles Hornfels - a metamorphic rock formed by heating by an igneous rock Litchfieldite - nepheline syenite gneiss Marble - a metamorphosed limestone Migmatite - a high grade metamorphic rock verging upon melting into a magma Mylonite - a metamorphic rock formed by shearing Metapelite - a metamorphic rock with a protolith of clay-rich (siltstone) sedimentary rock Metapsammite - a metamorphic rock with a protolith of quartz-rich (sandstone) sedimentary rock Phyllite - a low grade metamorphic rock composed mostly of micaceous minerals Pseudotachylite - a glass formed by melting within a fault via friction Quartzite - a metamorphosed sandstone typically composed of >95% quartz Schist - a low to medium grade metamorphic rock Serpentinite - a metamorphosed ultramafic rock dominated by serpentine minerals Skarn - a metasomatic rock 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 Whiteschist - a high pressure metamorphic rock containing talc and kyanite

Specific varieties of rocks

The following are terms for rocks that 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 lithified E horizon of a palaeosol formed from sandy soil Gossan - the product of the weathering of a sulfide rock or ore body Hyaloclastite – volcanic glass with basaltic composition 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 Lapis lazuli - a rock composed of lazulite and other minerals Larvikite - a variety of monzonite with microperthitic ternary feldspars from Larvik, Norway Litchfieldite - a metamorphosed nepheline syenite occurrence near Litchfield, Maine Llanite - a hypabyssal rhyolite with microcline and blue quartz phenocrysts from the Llano Uplift in Texas 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 type of chert found in Oklahoma, Arkansas and Texas Pyrolite - a chemical analogue considered to theoretically represent the earth's upper mantle Rapakivi granite - a granite containing crystals of orthoclase, which are mantled by oligoclase Rhomb porphyry - a type of latite with euhedral rhombic phenocrysts of feldspar Shonkinite - melitilic and kalsititic rocks Taconite - banded iron formation, primarily used in the United States of America Tachylite - basaltic volcanic glass Teschenite - a silica undersaturated, analcime bearing gabbro Theralite - a nepheline gabbro Unakite - an altered granite Variolite - devitrified glass Vogesite - a variety of lamprophyre Wad - rock rich in manganese oxide or manganese hydroxide