quartzite

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quartzite,

usually 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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 composed of firmly cemented quartz grains. Most often it is white, light gray, yellowish, or light brown, but is sometimes colored blue, green, purple, or black by included minerals. It results from the metamorphism of pure quartz sandstonesandstone,
sedimentary rock formed by the cementing together of grains of sand. The usual cementing material in sandstone is calcium carbonate, iron oxides, or silica, and the hardness of sandstone varies according to the character of the cementing material; quartz sandstones
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. It is most easily distinguished from sandstone by the fact that it fractures across its constituent grains of sand, while sandstone fractures along the line of the cementing material between the grains of sand. Although most quartzites are metamorphic, some are sedimentary in origin, resulting from cementation of quartz sandstone by groundwater solutions containing pure quartz.
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quartzite

A variety of sandstone composed largely of granular quartz cemented by silica, forming a homogeneous mass of very high tensile and crushing strengths; used as a building stone and as an aggregate in concrete. See also: Stone
Illustrated Dictionary of Architecture Copyright © 2012, 2002, 1998 by The McGraw-Hill Companies, Inc. All rights reserved
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Quartzite

 

a regionally metamorphosed rock composed mainly of quartz grains that are macroscopically indistinguishable from each other and form a uniform dense mass with a splintery or conchoidal fracture.

In addition to quartz, quartzite often contains other minerals that are used to distinguish special varieties of quartzite; they include mica, garnet, and hornblende. The formation of quartzite is associated with the recrystallization of sandstone in the process of regional metamorphism. Quartzite also includes certain siliceous rocks that are products of the cementation of quartz grains by opal or that are products of the metasomatic replacement of limestone and other calcareous rock by silica. Ferruginous quartzites that, in addition to quartz, contain hematite or magnetite, are formed as a result of the recrystallization of ferruginous sandstones or siliceous schists. Quartzites are characterized by a high SiO2 content (95–99 percent) and by high refractoriness (up to 1710°-1770°C) and mechanical strength; their compressive strength is 100–455 meganewtons/m2 (1,000–4,550 kg/cm2).

Quartzites occur in various metamorphic rocks in the form of solid sheetlike bodies extending for great distances. Quartzites are particularly widely found in Proterozoic deposits. Many varieties of quartzite are valuable minerals. Ferruginous (magnetitic) quartzites are a most important iron ore (for example, the deposits of Krivoi Rog and the Kursk Magnetic Anomaly in the USSR, Lake Superior in the United States, and Labrador in Canada). Quartzites in which the SiO2 content reaches 98–99 percent are used for manufacturing dinas refractories, for obtaining metallic silicon and its alloys, and as a flux in metallurgy. (Deposits of pure quartzites are found in the Urals, in Karelia, and elsewhere.) Quartzites are also widely used in construction as a decorative stone. (For example, the Lenin Mausoleum and a number of the Moscow subway stations have been faced with the pink-red Shoksha quartzite.) Certain types of quartzite are used as an abrasive material.

REFERENCE

Kurs mestorozhdenii nemetallicheskikh poleznykh iskopaemykh. Edited by P. M. Tatarinov. Moscow, 1969.

A. B. PAVLOVSKII

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.

quartzite

[′kwȯrt‚sīt]
(petrology)
A granoblastic metamorphic rock consisting largely or entirely of quartz; most quartzites are formed by metamorphism of sandstone.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

quartzite

A variety of sandstone composed largely of granular quartz which is cemented by silica forming a homogeneous mass of very high tensile and crushing strengths; esp. used as a building stone, as gravel in road construction, and as an aggregate in concrete.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.
References in periodicals archive ?
Soils formed from quartzite were characterised by a lower SSA than those formed from schist, at both altitudes.
Furthermore, the soil formed from quartzite on the summit had a much darker colour (e.g.
A three-fold subdivision of the Abbottabad Formation has emerged through this study; a) lower arenaceous unit (dominantly quartzite with subordinate pebbly conglomerate sandstone and siltstone) b) middle dolomitic unit (dominantly dolomite with subordinate quartzite siltstone and conglomerate) and c) upper quartzite unit.
The Tanawal Formation consists of quartzite speckled quartzite quartzose sandstone argillaceous sandstone phyllite shale and quartzose conglomerate.
The company said that the Bratsk Ferroalloy Plant had won the tender for the rights to utilise the subsoil plot on the Uvatsk deposit of quartzite and quartz sandstones in May 2008.
The geoelectrical sections (Figure 6) delineated four subsurface layers composed of topsoil/weathered layers, fresh quartzite, fractured/faulted quartzite and the fresh quartzite bedrock.
The map displays high resistivity (2,494-7,407 ?m) (typical of fresh massive quartzite) on the western flank and relatively low resistivity (263-1,896 ?m) (characteristic of fractured quartzite) on the eastern flank.
It represents highly kaolinized angular quartzite fragments scattered in clayey-silty matrix.
It represents angular quartzite fragments accompanied with sporadic slate fragments, both scattered in silty-clayey matrix.
Although invasively flaked biface points (mean: 45.8 mm) as a whole (all raw materials) are shorter than all invasively flaked uniface points (mean: 47 mm), if we compare similar materials, say quartzite and silcrete, biface points (mean: 51 mm) are longer on average than uniface points (mean: 36.5 mm).
This group consists of one quartzite (E33045) and three brown glass (E33061, E4438A, E4438C) points with no traces of use, no hafting resin, no ochre and no wrapping traces.
Several parallel, clearly visible layers of quartz run at a short distance from one another in an ENE direction between the otherwise hardly visible rock, the quartzite I was sorry to be unable to retrieve some of the rock containing ore from any depth, as I suspect the presence of silver here.