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Schist metamorphosed from mudstone is particularly common and is often very rich in mica (a mica schist). Where the type of the original rock (the protolith) is discernible, the schist is usually given a name reflecting its protolith, such as schistose metasandstone.
Chlorite schist, a type of greenschist Greenschist (prasinite) at Cap Corse in Corsica, France Greenschist (epidote) from Itogon, Benguet, Philippines. Greenschists are metamorphic rocks that formed under the lowest temperatures and pressures usually produced by regional metamorphism, typically 300–450 °C (570–840 °F) and 2–10 kilobars (29,000–145,000 psi). [1]
Some rock types containing chlorite, such as chlorite schist, have minor decorative uses or as construction stone. However, chlorite is a common mineral in clay, which has a vast number of uses. [9] Chlorite schist has been used as roofing granules, the mineral granules adhered to asphalt composition shingles due to the green color.
Gneiss – Common high-grade metamorphic rock; Granulite – Class of high-grade medium to coarse grained metamorphic rocks; Greenschist – Metamorphic rock – A mafic metamorphic rock dominated by green amphiboles; Hornfels – Group of metamorphic rocks Calcflinta – A type of hornfels found in the Scottish Highlands
Mica is common in igneous and metamorphic rock and is occasionally found as small flakes in sedimentary rock. [6] It is particularly prominent in many granites, pegmatites, and schists, [7] and "books" (large individual crystals) of mica several feet across have been found in some pegmatites. [8]
Soapstone (also known as steatite or soaprock) is a talc-schist, which is a type of metamorphic rock. It is composed largely of the magnesium -rich mineral talc . It is produced by dynamothermal metamorphism and metasomatism , which occur in subduction zones , changing rocks by heat and pressure, with influx of fluids but without melting.
For instance, actinolite amphibole is a common product of retrograde metamorphism of metabasalt at (upper) greenschist facies conditions. Often, this will take on the crystal form and habit of the original protolith assemblage; actinolite pseudomorphically replacing pyroxene is an indication that the amphibolite may not represent a peak ...
Blueschist on Île de Groix, France Photomicrograph of a thin section of blueschist facies metamorphosed basalt, from Sivrihisar, Turkey. Blueschist (/ ˈ b l uː ʃ ɪ s t /), also called glaucophane schist, is a metavolcanic rock [1] that forms by the metamorphism of basalt and rocks with similar composition at high pressures and low temperatures (200–500 °C (392–932 °F ...