List of rock types recognized by geologists
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.
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
- Appinite – Type of igneous rock – A group of varieties of lamprophyre, mostly rich in hornblende
- Aphanite – Igneous rock composed of very small crystals invisible to the naked eye
- Borolanite – Variety of nepheline syenite from Loch Borralan, Scotland – A variety of nepheline syenite from Loch Borralan, Scotland
- Blue Granite – Variety of monzonite, an igneous rock
- Epidosite – Hydrothermally altered epidote- and quartz-bearing rock
- Felsite – Very fine-grained volcanic rock that sometimes contains larger crystals
- Flint – Cryptocrystalline form of the mineral quartz
- Ganister – Hard, fine-grained quartzose sandstone, or orthoquartzite
- Gossan – Intensely oxidized, weathered or decomposed rock
- Hyaloclastite – Volcaniclastic accumulation or breccia
- Ijolite – Igneous rock consisting essentially of nepheline and augite
- Jadeitite – Metamorphic rock found in blueschist-grade metamorphic terranes
- Jasperoid – A hematite-silica metasomatite analogous to a skarn
- Kenyte – Type of igneous rock - A variety of phonolite, first found on Mount Kenya
- Lapis lazuli – Metamorphic rock containing lazurite, prized for its intense blue color - A rock composed of lazurite and other minerals
- Larvikite – Variety of monzonite, an igneous rock
- Litchfieldite – A metamorphosed nepheline syenite occurrence near Litchfield, Maine
- Llanite – Type of mineral – A hypabyssal rhyolite with microcline and blue quartz phenocrysts from the Llano Uplift in Texas
- Luxullianite – Rare type of granite
- Mangerite – Plutonic intrusive igneous rock, that is essentially a hypersthene-bearing monzonite
- Minette – A variety of lamprophyre
- Novaculite – Type of rock – A type of chert found in Oklahoma, Arkansas, and Texas
- 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
- Rapakivi granite – Type of igneous rock
- 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
- Rodingite – metamorphic rockPages displaying wikidata descriptions as a fallback – A mafic rock metasomatized by serpentinization fluids
- Shonkinite – Intrusive igneous rock – melitilic and kalsititic rocks
- Taconite – Variety of iron-bearing sedimentary rock
- Tachylite – Form of basaltic volcanic glass
- Teschenite – Type of igneous rock – A silica undersaturated, analcime bearing gabbro
- Theralite – Igneous rock – A nepheline gabbro
- Unakite – Multicoloured metamorphic rock – An altered granite
- Variolite – Igneous rocks which contain varioles
- Vogesite – Ultrapotassic igneous rocks – A variety of lamprophyre
- Wad (mineral) – Porous secondary manganese oxyhydroxide – A rock rich in manganese oxide or manganese hydroxide