The following is a list of rock types recognized by . 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.
Igneous rocks
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- Igneous rock belonging to basalt family
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– Basaltic lava with a crumpled appearance
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– Basaltic lava with a flowing, often ropy appearance
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– An ultramafic, ultrapotassic intrusive rock dominated by mafic in a feldspar groundmass
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– A silica-undersaturated form of andesite
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– An ultramafic rock, essentially a peridotite
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An intrusive igneous rock intermediate in composition between diorite and monzonite
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– A silica-undersaturated granite with <5% normative quartz
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– a plutonic rock with <5% normative quartz
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– A silica-undersaturated plutonic rock of nepheline and alkali feldspar
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– A silica-undersaturated plutonic rock with >90% nepheline
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– A hypersthene-bearing gabbro
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– A silica-undersaturated volcanic rock; essentially similar to nepheline syenite
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– A volcanic rock with a composition between phonolite and tephrite
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– An olivine-bearing basalt
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- a coarse grained plutonic rock composed of >90% pyroxene
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– A diorite with >5% modal quartz
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– An intermediate plutonic rock, essentially a monzonite with 5–10% modal quartz
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– An intrusive rock composed mostly of quartz
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– A felsic volcanic rock which is intermediate between a rhyolite and a dacite
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– a plutonic rock
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– A coarse-grained carbonatite rock
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– A plutonic rock dominated by orthoclase feldspar; a type of granite
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of the granite family
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– Essentially a basaltic glass
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– A volcanic rock with a composition between phonotephrite and phonolite
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– A silica-undersaturated volcanic rock
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– A plagioclase-dominant granitoid
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– An alkaline intermediate volcanic rock
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– A volcanic rock with a composition between basalt and trachyte
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– a sodic type of trachybasalt, typically formed by ocean island (hot spot) volcanism
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– A silica-undersaturated volcanic rock; essentially a feldspathoid-bearing rhyolite
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– A plutonic ultramafic rock containing olivine, pyroxene and plagioclase
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– A form of tonalite where plagioclase-group feldspar is oligoclase
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- Glassy igneous rock with phenocrysts
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– A type of pyroxenite, composed of clinopyroxene and orthopyroxene
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- An ultramafic plutonic or cumulate rock, a type of peridotite, composed of olivine and clinopyroxene
Sedimentary rocks
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– A non-detrital sedimentary rock that contains high amounts of phosphate minerals
Metamorphic rocks
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– A rock formed by faulting
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– A mafic metamorphic rock dominated by green amphiboles
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– Nepheline syenite gneiss
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– a metamorphosed limestone
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– A metamorphic rock formed by shearing
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- A type of metamorphic rock formed through the recrystallization of conglomerates
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– A metamorphic rock with a protolith of clay-rich (siltstone) sedimentary rock
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Metapsammite – A metamorphic rock with a protolith of quartz-rich (sandstone) sedimentary rock
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– A low grade metamorphic rock composed mostly of minerals
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– A glass formed by melting within a fault via friction
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– A metamorphosed sandstone typically composed of >95% quartz
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– that falls between pelitic (clay-rich) and psammitic (sand-rich) compositions
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- A low grade metamorphic rock formed from shale or silt
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– A rock formed by partial melting during a Impact event
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– A metamorphosed ultramafic rock with talc as an essential constituent; similar to a serpentinite
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– A rock whose fabric reflects the history of its deformation
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– A high pressure metamorphic rock containing talc and kyanite
Specific varieties
The following are terms for rocks that are not
Petrography 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.
See also
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: for a list of unusual or culturally significant rock outcrops
External links
