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.
The Columbia Electronic Encyclopedia™ Copyright © 2013, Columbia University Press. Licensed from Columbia University Press. All rights reserved. www.cc.columbia.edu/cu/cup/

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 It might be outdated or ideologically biased.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 ?
Laetitia Delaloye, head of antiquities of Christie's, poses for a photograph with an Egyptian brown quartzite head of the God Amen prior to its' sale at Christie's auction house in London Image Credit: Reuters
Hydroxyl-interlayered vermiculite also occurred in all soils and was especially relevant in the quartzite soil on the summit, probably resulting from direct alteration of illites.
Quartzite in its purest form is harder than granite but is quite porous and will stain easily, however what is being sold on the market is not pure quartzite, but is mixed with calcite, like marble and travertine and will also etch with acidic liquids.
Today one of his grandsons, Michael Back, runs the Backsberg Estate Cellars winery in the foothills of the rugged, quartzite Drakenstein Mountains, 35 miles northwest of Cape Town.
Pursuant to the agreement, the company said it will acquire the WPE No1 and No2 Claims in the Middlecamp Mining District in La Paz County, near Quartzite Arizona , which cover a total of 40 acres and have access between Phoenix and Palm Springs, California, along Interstate 10.
The sarcophagus chamber, of red quartzite quarried and transported to Abydos from Gebel Ahmar (near modern Cairo), could be dated to the late Middle Kingdom, but its owner remained unidentified.
Archaeologists now know that the giant quartzite sarcophagus chamber derives from a royal tomb built originally for a pharaoh Sobekhotep-probably Sobekhotep I, the first king of Egypt's 13th Dynasty.
A handout picture released by Egypt's Supreme Council of Antiquities yesterday shows the quartzite sarcophagus of Sobekhotep I.
From the summit of Cruach Scarba (449m), the superb visibility allowed me to capture Ben Cruachan in the east and north to the distinctive quartzite slopes of the Grey Corries and to Ben Nevis beyond.
The sum of investments on development of mineral resources base of quartzite and construction of metallurgical plant comprises $61.7 million.
The main difference of the two types of target material (quartzite and sandstone) is porosity, which poses a challenge in modeling the material behavior under highly dynamic conditions.
Butler, a former newspaper executive who lives in Willisville, said he wanted to ensure Vale "gets the credit they deserve" for preserving an area that is enjoyed by hundreds of people every year who hike, photograph and paint the ancient mountain range, which boasts striking outcrops of white quartzite.