pegmatite

[ peg-muh-tahyt ]

noun

, Petrology.

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

pegmatite

/ 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

pegmatite

/ 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.

Derived Forms

• pegmatitic, adjective

Other Words From

• peg·ma·tit·ic [peg-m, uh, -, tit, -ik], adjective

Word History and Origins

Origin of pegmatite¹

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

Word History and Origins

Origin of pegmatite¹

C19: from Greek pegma something joined together

Example Sentences

Chrysoberyl is known as a constituent of certain kinds of granite, pegmatite and gneiss.

From Project Gutenberg

Pegmatite and Porphyry (with a very few small crystals of felspar) and Gneiss?

From Project Gutenberg

I observed Pegmatite of a white colour, and hornblende Porphyry and Diorite.

From Project Gutenberg

The hills on which I stood were composed of Pegmatite, with patches of white Mica in large leaflets.

From Project Gutenberg

In one of the creeks I observed pegmatite; pebbles of talc-schiste and of white quartz covered the bed of the river.

From Project Gutenberg