The Collaborative International Dictionary of English v.0.48:
Oligoclase \Ol"i*go*clase\, n. [Oligo- + Gr. ? fracture, fr. ? to break.] (Min.) A triclinic soda-lime feldspar. See Feldspar. [1913 Webster]WordNet (r) 3.0 (2006):
oligoclase n 1: any of a series of triclinic feldspars that form rocks [syn: plagioclase, oligoclase]