A0322200 (ăn-ôr′thīt)n. A white to gray variety of plagioclase feldspar that contains a high proportion of calcium to sodium and occurs in alkaline igneous rocks such as gabbro and anorthosite.[From Greek an-, not; see a-1 + orthos, straight (from its oblique crystals).]an′or·thit′ic(-thĭt′ĭk) adj.Thesaurus
anorthitic - characteristic of anorthite