plagioclase[plā′jē ō klās′]
any of a series of triclinic feldspars, ranging in composition from albite to anorthite and found in many rocks
Origin of plagioclaseGerman plagioklas ; from Classical Greek plagios (see plagio-) + klasis, a cleaving, fracture ; from klaein, to break: see clastic
(usually uncountable, plural plagioclases)
From plagio- +"Ž -clase, after German Plagioklas.