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 forms
pegmatitic (ˌpɛɡməˈtɪtɪk)
adjective
Word origin
C19: from Greek pegma something joined together
pegmatite in American English
(ˈpɛgməˌtaɪt)
noun
a light-colored, coarsegrained, intrusive igneous rock, usually granitic, containinglarge crystals of quartz, feldspar, and mica, and sometimes rare minerals: typically found in fissures of other igneous rocks
Derived forms
pegmatitic (ˌpegmaˈtitic) (ˈpɛgməˈtɪtɪk)
adjective
Word origin
< Gr pēgma (gen. pēgmatos), a framework, something fastened together (< IE base *paĝ-: see fang) + -ite1: from its texture