\Dol"er*ite\, n. [Gr. ? deceitful; because it was
easily confounded with diorite.] (Geol. & Min.)
A dark-colored, basic, igneous rock, composed essentially of
pyroxene and a triclinic feldspar with magnetic iron. By many
authors it is considered equivalent to a coarse-grained
basalt.

\Dol"er*ite\, n. [Gr. ? deceptive, because easily
confounded with diorite.] (Petrography)
   (a) A dark, crystalline, igneous rock, chiefly pyroxene
       with labradorite.
   (b) Coarse-grained basalt.
   (c) Diabase.
   (d) Any dark, igneous rock composed chiefly of silicates
       of iron and magnesium with some feldspar. --
       {Dol`er*it"ic}, a.