oligoclase

from WordNet (r) 3.0 (2006)

oligoclase
    n 1: any of a series of triclinic feldspars that form rocks
         [syn: {plagioclase}, {oligoclase}]

from 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]