a series of feldspar minerals consisting of a mixture of sodium and calcium aluminium silicates in triclinic crystalline form: includes albite, oligoclase, and labradorite
Derived forms
plagioclastic (ˌpleɪdʒɪəʊˈklæstɪk)
adjective
plagioclase in American English
(ˈpleɪdʒioʊˌkleɪs)
noun
any of a series of triclinic feldspars, ranging in composition from albite to anorthite and found in many rocks
Word origin
Ger plagioklas < Gr plagios (see plagio-) + klasis, a cleaving, fracture < klaein, to break: see clastic