Name:  Augite-Mica peridotite

Geologic Name:  None

Reference:  Miser, H.D., and Ross, C.S., Diamond-bearing peridotite in Pike
County, Arkansas: U.S. Geol. Survey Bull. 735, p. 279-322, 1923.

Microscopic characters:  Porphyritic texture.  The smaller olivine phenocrysts
are usually completely altered to serpentine; the largest have comparatively
fresh cores with the serpentine invading fractures.  The groundmass contains
an abundance of rod-like grains of augite and phlogopite sometimes altered
to chlorite.  Small yellow isometric cubes of perovskite are abundantly 
sprinkled throughout the groundmass.  Magnetite grains are plentiful.