granite

granite

1. a light-coloured coarse-grained acid plutonic igneous rock consisting of quartz, feldspars, and such ferromagnesian minerals as biotite or hornblende: widely used for building

2. another name for a stone

Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005

granite

An igneous rock having crystals or grains of visible size; consists mainly of quartz and mica or other colored minerals.

See also: Stone

Illustrated Dictionary of Architecture Copyright © 2012, 2002, 1998 by The McGraw-Hill Companies, Inc. All rights reserved

granite

[′gran·ət]

(petrology)

A visibly crystalline plutonic rock with granular texture; composed of quartz and alkali feldspar with subordinate plagioclase and biotite and hornblende.

McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

granite

1. An igneous rock having crystals or grains of visible size; consists mainly of quartz, feldspar, and mica or other colored minerals.

2. In the building stone industry, a crystalline silicate rock having visible grains; this includes gneiss and igneous rocks that are not granite in the strict sense.

McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Granite

 

a magmatic rock rich in silica.

One of the most common rocks of the earth’s crust, granite is composed of potash feldspar (orthoclase, microcline), acid plagioclase (albite, oligoclase), quartz, mica (biotite or muscovite), amphibole, and, more rarely, pyroxene. The structure of granite is usually holocrystalline and frequently por-phyraceous and gneissoid-banded. It is predominant among intrusive rocks and occupies an essential place in the geologic structure of the Urals, the Caucasus, the Ukraine, Karelia, the Kola Peninsula, Middle Asia, and Siberia. Granitic intrusions date from the Archean and Cenozoic eras. Granite usually occurs in rocks in the form of batholiths, laccoliths, bosses, and veins. During the formation and cooling of the granitic bodies a regular system of joints arises; the jointing is. as a result, characteristically parallelepipedal, columnar, or sheetlike in natural exposures. The rounding of corners through weathering forms hammock jointing. The weathering of granite takes the form of disintegration or kaolinization. Deeper changes in the granite can be produced by pneumatolytic processes, resulting in the formation of greisen with lithia mica or tourmaline.

The origin of granite, in addition to its scientific interest, has great practical importance, since certain granitic bodies are associated with deposits of various valuable metals, such as tin, wolfram, molybdenum, lead, and zinc. Pegmatitic veins, which in certain cases are sources of rare-metal mineralization and high quality raw materials for ceramics (for example, feldspar, mica, and muscovite), are associated genetically with granite.

Because of its physical and mechanical properties, granite is an excellent building material. Its massiveness. density, and wide textural potentials (the ability to take on a mirrorlike polish, on which light brings out the play of colors of the ingrained mica, or the sculptural expressiveness of the unpolished rough stone, which absorbs light) make granite one of the basic materials for monumental sculpture. Granite is also used in obelisks, columns, and as a facing for many buildings. Most of the granite used in the USSR comes from quarries in the Ukraine, the Urals, and Karelia.

REFERENCES

Levinson-Lessing, F. Iu. Izbrannye trudy, vol. 4: Petrografiia. 1955.
Menert, K. Novoe o probleme granitov. Moscow, 1963. Petrov, V. P. “Sovremennoe sostoianie predstavlenii o magme i problema granita.” Izv. AN SSSR: Ser. geol., 1964. no. 3.

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