noun Petrology.

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

Origin of pegmatite

1825–35; < Greek pēgmat- (stem of pêgma) anything fastened together, a bond (compare pēgnýein to stick) + -ite1
Related formspeg·ma·tit·ic [peg-muh-tit-ik] /ˌpɛg məˈtɪt ɪk/, adjective Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for pegmatite

Historical Examples of pegmatite

British Dictionary definitions for pegmatite



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
Derived Formspegmatitic (ˌpɛɡməˈtɪtɪk), adjective

Word Origin for pegmatite

C19: from Greek pegma something joined together
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

pegmatite in Science



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.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.