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Longman Dictionary of Contemporary English
▪ Near the waterline, the rushing waters have polished the schist to gunmetal, and carved it into fantastic flutes and chambers.
The Collaborative International Dictionary

Schist \Schist\ (sh[i^]st), n. [Gr. ? divided, divisible, fr. ? to divide: cf. F. schiste. See Schism.] (Geol.) Any crystalline rock having a foliated structure (see Foliation) and hence admitting of ready division into slabs or slates. The common kinds are mica schist, and hornblendic schist, consisting chiefly of quartz with mica or hornblende and often feldspar.

Douglas Harper's Etymology Dictionary

type of layered metamorphic rock, 1795 (earlier schistus, c.1600), from French schiste (16c.), from Latin schistos lapis "stone that splits easily" (Pliny), from Greek skhistos "divided, separated," from skhizein "to split" (see shed (v.)). The rock splits easily in layers. Liddell & Scott say Greek skhistos lithos was "probably talc."


n. Any crystalline rock having a foliated structure and hence admitting of ready division into slabs or slates.


n. any metamorphic rock that can be split into thin layers


Schist (pronounced ) is a medium-grade metamorphic rock with medium to large, flat, sheet-like grains in a preferred orientation (nearby grains are roughly parallel). It is defined by having more than 50% platy and elongated minerals, often finely interleaved with quartz and feldspar. These lamellar (flat, planar) minerals include micas, chlorite, talc, hornblende, graphite, and others. Quartz often occurs in drawn-out grains to such an extent that a particular form called quartz schist is produced. Schist is often garnetiferous. Schist forms at a higher temperature and has larger grains than phyllite. Geological foliation (metamorphic arrangement in layers) with medium to large grained flakes in a preferred sheetlike orientation is called schistosity.

The names of various schists are derived from their mineral constituents. For example, schists rich in mica are called mica schists and include biotite or muscovite. Most schists are mica schists, but graphite and chlorite schists are also common. Schists are also named for their prominent or perhaps unusual mineral constituents, as in the case of garnet schist, tourmaline schist, and glaucophane schist.

The individual mineral grains in schist, drawn out into flaky scales by heat and pressure, can be seen with the naked eye. Schist is characteristically foliated, meaning that the individual mineral grains split off easily into flakes or slabs. The word schist is derived ultimately from the Greek word σχίζειν schízein meaning "to split", which is a reference to the ease with which schists can be split along the plane in which the platy minerals lie.

Most schists are derived from clays and muds that have passed through a series of metamorphic processes involving the production of shales, slates and phyllites as intermediate steps. Certain schists are derived from fine-grained igneous rocks such as basalts and tuffs.

Schists are frequently used as dimension stone, which is stone that has been selected and fabricated to specific shapes or sizes.

Usage examples of "schist".

Through the bars of the cage, Marchpane saw among the layers of schist a seam of glass catch at the lamplight, and then another.

They consist chiefly of granulitic quartzose schists and felspathic gneisses, permeated in places by strings and veins of pegmatite.

It was not until perhaps an hour after dark that the vehicle finally slowed, coming to rest on a flat outcropping of pale schist.

The Archean, composed of gneiss and crystalline schists, and traversed by eruptive veins, extends over the greater part of the Eastern Rumelian plain, the Rilska Planina, Rhodope, and the adjacent ranges.

Built mainly in blocks of slatelike schist cemented with banco, their interior walls had been decorated with a yellow plaster of which a little is still preserved.

String of the underground river was lost to them beneath layers upon layers of boulders, seeping, winding, bifurcating and rejoining, weaving its thousand threads along the schist floor far below.

It is, therefore, tolerably certain that the underlying older formation of gneisses, crystalline schists and granites, etc.

She knew that metamorphic rocks broke that way, but schists and such were generally too weak to make good tools.

Rude stone walls supported cedar poles for rafters and tiles of mica schist for the roof.

Very little rock and none of it blasted or chipped, no limestone or Manhattan mica schist.

Through shale, through coal, through marble, through mica schist, through quartzite.

It was a twisted white pine that was growing out of the juncture of another decaying quartz vein and the schist it was intruded into, which was weaker.

Near Saalfeld (less than ten miles from the Ring of Fire) are some interesting metamorphic quartzites and schists near the Kamsdorf mine, and the Jeramiah's Gluck mine (Feengrotten).

Limestone, sandstone, medium-grade schists, and other metamorphics down below at this end of the Med.