Name:   Hornblende Granite

Geologic Name:  Quincy Granite

Reference: Clapp, C.H., Geology of the igneous rocks of Essex County, Massachusetts:
U.S. Geol. Survey, Bull. 704, p. 71-85, 1921.

Microscopic characters:  Hypautomorphic-granular texture.  The most abundant
constituent is a microcline microperthite.  Large quartz grains show undulatory 
extinction.  A few individual grains of plagioclase occur.  Biotite and hornblende
are closely associated with magnetite, zircon and large grains of fluorite.