The following is a list of rock types recognized by geologists. There is no agreed number of specific types of rock. Any unique combination of chemical composition, mineralogy, grain size, texture, or other distinguishing characteristics can describe a rock type. Additionally, different classification systems exist for each major type of rock.[1] There are three major types of rock: igneous rock, metamorphic rock, and sedimentary rock.
Anorthosite – Mafic intrusive igneous rock composed predominantly of plagioclase
Aplite – Fine-grained intrusive igneous rock type similar to granite
Basalt – Magnesium- and iron-rich extrusive igneous rock
ʻAʻā – Molten rock expelled by a volcano during an eruptionPages displaying short descriptions of redirect targets – Basaltic lava with a crumpled appearance
Pāhoehoe – Molten rock expelled by a volcano during an eruptionPages displaying short descriptions of redirect targets – Basaltic lava with a flowing, often ropy appearance
Basaltic trachyandesite – Naming system for volcanic rocksPages displaying short descriptions of redirect targets
Lamproite – Mantle rock expulsed to the surface in volcanic pipes
Lamprophyre – Ultrapotassic igneous rocks – An ultramafic, ultrapotassic intrusive rock dominated by mafic phenocrysts in a feldspar groundmass
Latite – Type of volcanic rock – A silica-undersaturated form of andesite
Lherzolite – an ultramafic and ultrabasic rock that is composed of olivine and pyroxenePages displaying wikidata descriptions as a fallback – An ultramafic rock, essentially a peridotite
Monzogranite – Biotite granite rocks that are considered to be the final fractionation product of magma – A silica-undersaturated granite with <5% normative quartz
Monzonite – Igneous intrusive rock with low quartz and equal plagioclase and alkali feldspar – a plutonic rock with <5% normative quartz
Pegmatite – Igneous rock with very large interlocked crystals
Peridotite – Coarse-grained ultramafic igneous rock type
Phonolite – Uncommon extrusive rock – A silica-undersaturated volcanic rock; essentially similar to nepheline syenite
Phonotephrite – strongly alkaline volcanic rock with a composition between phonolite and tephritePages displaying wikidata descriptions as a fallback – A volcanic rock with a composition between phonolite and tephrite
Picrite – Variety of high-magnesium basalt that is very rich in the mineral olivinePages displaying short descriptions of redirect targets – An olivine-bearing basalt
Porphyry – Textural form of igneous rock with large grained crystals in a fine matrix
Pumice – Extremely vesicular volcanic rock, typically light-colored
Pyroxenite – Igneous rock - a coarse grained plutonic rock composed of >90% pyroxene
Quartz diorite – Igneous, plutonic rock – A diorite with >5% modal quartz
Quartz monzonite – Type of igneous rock – An intermediate plutonic rock, essentially a monzonite with 5–10% modal quartz
Quartzolite – Extremely rare igneous rock made mostly of quartz – An intrusive rock composed mostly of quartz
Rhyodacite – Volcanic rock rich in silica and low in alkali metal oxides – A felsic volcanic rock which is intermediate between a rhyolite and a dacite
Rhyolite – Igneous, volcanic rock, of felsic (silica-rich) composition
Comendite – Hard, peralkaline igneous rock, a type of light blue grey rhyolite
Pantellerite – Peralkaline rhyolite type of volcanic rock
Phosphorite – Sedimentary rock containing large amounts of phosphate minerals – A non-detrital sedimentary rock that contains high amounts of phosphate minerals
Marble – Type of metamorphic rock – a metamorphosed limestone
Migmatite – Mixture of metamorphic rock and igneous rock
Mylonite – Metamorphic rock – A metamorphic rock formed by shearing
Metapelite – Metamorphic rockPages displaying short descriptions of redirect targets – 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 – Type of foliated metamorphic rock – A low grade metamorphic rock composed mostly of micaceous minerals
Pseudotachylite – Glassy, or very fine-grained, rock typePages displaying short descriptions of redirect targets – A glass formed by melting within a fault via friction
Quartzite – Hard, non-foliated metamorphic rock – A metamorphosed sandstone typically composed of >95% quartz
Schist – Easily split medium-grained metamorphic rock
Serpentinite – Rock formed by transformation of olivine
Soapstone – Talc-bearing metamorphic rock – Essentially a talc schist
Tectonite – Rock type – A rock whose fabric reflects the history of its deformation
Whiteschist – Type of metamorphic rock – A high pressure metamorphic rock containing talc and kyanite
Specific varieties
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 – Type of igneous rockPages displaying short descriptions of redirect targets – A variety of quartz monzonite
Pietersite – Commercial term for a variety of chalcedony
Pyrolite – theoretical rock making up the earth's upper mantlePages displaying wikidata descriptions as a fallback – A chemical analogue considered to theoretically represent the Earth's upper mantle
Rhomb porphyry – Textural form of igneous rock with large grained crystals in a fine matrixPages displaying short descriptions of redirect targets – A type of latite with euhedral rhombic phenocrysts of feldspar
