pegmatite

American  

[peg-muh-tahyt] / ˈpɛg məˌtaɪt /

noun

Petrology.

1. a coarsely crystalline granite or other high-silica rock occurring in veins or dikes.

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pegmatite British  

/ ˈpɛɡməˌtaɪt, ˌpɛɡməˈtɪtɪk /

noun

1. any of a class of exceptionally coarse-grained intrusive igneous rocks consisting chiefly of quartz and feldspar: often occurring as dykes among igneous rocks of finer grain

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pegmatite Scientific  

/ pĕg′mə-tīt′ /

1. Any of various coarse-grained igneous rocks that often occur as wide veins cutting across other types of rock. Pegmatites form from water-rich magmas or lavas that cool slowly, allowing the crystals to grow to large sizes. Although pegmatites can be compositionally similar to a number of rocks, they most often have the composition of granite.

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Other Word Forms

• pegmatitic adjective

Etymology

Origin of pegmatite

1825–35; < Greek pēgmat- (stem of pêgma ) anything fastened together, a bond (compare pēgnýein to stick) + -ite ¹

Example Sentences

Barroso, a world heritage site for agriculture since 2018, is one of many lithium-rich areas in northern Portugal and Savannah already mines feldspar, quartz and pegmatite there.

From Reuters • Jun. 8, 2022

A rock that chiefly consists of pegmatitic texture is known as a pegmatite.

From Textbooks • Jan. 1, 2017

From a builder’s point of view, schist and pegmatite are a blessing as well as a curse.

From New York Times • Jul. 2, 2014

About 45 million years ago, another episode of magmatism sent dikes of granitic pegmatite through the orthogneiss.

From Scientific American • Mar. 7, 2012

Tungsten is likewise found in original segregations in igneous rocks and in pegmatite dikes, but these deposits are of comparatively small commercial importance.

From The Economic Aspect of Geology by Leith, C. K. (Charles Kenneth)