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Related to anorthite: labradorite
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.
(Minerals) a white to greyish-white or reddish-white mineral of the feldspar group and plagioclase series, found chiefly in igneous rocks and more rarely in metamorphic rocks. It is used in the manufacture of glass and ceramics. Composition: calcium aluminium silicate. Formula: CaAl2Si2O8. Crystal structure: triclinic
[C19: from an- + ortho- + -ite1]
a white or gray feldspar mineral, CaAl2Si2O8, calcic plagioclase.
an`or•thit′ic (-ˈθɪt ɪk) adj.