schist

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Related to Schists: Mica schist, Gneisses

schist

(shĭst), metamorphic rockrock,
aggregation of solid matter composed of one or more of the minerals forming the earth's crust. The scientific study of rocks is called petrology. Rocks are commonly divided, according to their origin, into three major classes—igneous, sedimentary, and metamorphic.
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 having a foliated, or plated, structure called schistosity in which the component flaky minerals are visible to the naked eye. Schists are distinguished from the other foliated rocks, slates and gneisses, by the size of their mineral crystals; these are larger than those of slates, being visible to the naked eye, but smaller than those of gneisses, which are coarsely foliated rocks as opposed to finely foliated, or schistose, rocks. As contrasted with the folia of slates, the folia of schists are rough-surfaced and irregular. Schists split readily along their planes of schistosity, like slates along cleavage lines. Like other foliated rocks, schists owe their origin to the metamorphism of preexisting rocks. The commonest of the schists is mica schist, the essential minerals of which are quartzquartz,
one of the commonest of all rock-forming minerals and one of the most important constituents of the earth's crust. Chemically, it is silicon dioxide, SiO2.
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 and micamica
, general term for a large group of minerals, hydrous silicates of aluminum and potassium, often containing magnesium, ferrous iron, ferric iron, sodium, and lithium and more rarely containing barium, chromium, and fluorine.
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 (biotite or muscovite). Other schists are hornblende schist, talc schist, chlorite schist, and graphite schists. Schists are abundant in the Precambrian (Archean and Proterozoic) rocks.
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schist

[shist]
(geology)
A large group of coarse-grained metamorphic rocks which readily split into thin plates or slabs as a result of the alignment of lamellar or prismatic minerals.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

schist

A rock, the constituent minerals of which have assumed a position in more or less closely parallel layers or folia; due to metamorphic action; used principally for flagging.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.

schist

any metamorphic rock that can be split into thin layers because its micaceous minerals have become aligned in thin parallel bands
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
References in periodicals archive ?
For example, for schists, the oriented structure of which is most pronounced, [D.sub.sc] = 0.56 [+ or -] 0.20.
As shown schematically in Figure 1(a), the green schist stratum and coal seam stratum are assembled by placing the elementary slabs in layers with perfectly mated interfaces.
Schist constitutes the same predominant substratum in the sampling area.
There has been no prior research on the chromium-rich beryl [B[e.sub.3]A[l.sub.2][(Si[O.sub.3).sub.6]] in the schists from the Halilbagi area (which are in tectonic contact with ophiolites), although Prime Ministry Archives (1993) reported that emeralds (a green gem variety of beryl) were discovered and mined in the Sivrihisar area during the Ottoman Empire.
All selected soils are deep, basalt derived Bidar soil is moderately deep and the schist derived Hira and the limestone derived Shahabad soils are deep.
The schists and quartz-schists (Esquistos Grises de Punta Claditas and Esquistos Grises de la Gruta, after Rebolledo and Charrier, 1994) consist of quartz, white-mica, chlorite, albite and garnet (Grt1 [+ or -] Grt2), with tourmaline, epidote, apatite, zircon, titanite, ilmenite and rutile as accessory minerals.
It consists of green schists parasitized by loess deposits where the rivers deepened and branched a lot, reaching to Proterozoic green schist, emphasizing the current geomorphological processes.
The northern part lies in a hilly area where the geologic substrate is pelitic schist of the Precambrian "flyschoid series" (Orapu schist of Armina series [9, 10]).
Prominent rock units include granite gneiss, migmatites, schist/ quartz schist, porphyritic granite, fine-medium grained granite and charnockite.
Schists have been used globally for the manufacture of stone artefacts, including axes, adzes and cutting tools (Reedy 2008).