Name:   Mica Dacite Porphyry

Geologic Name:  None

Reference: None

Microscopic characters:   Porphyritic texture.  Large phenocrysts of quartz,
and euhedral crystals of andesine and biotite are embedded in a fine
crystalline groundmass.  The andesine is quite fresh with some alteration
to kaolin and paragointe.  Both carlsbad and albite twinning are common.
The biotite often shows alteration to chlorite and epidote is frequently
intergronw with it.  The groundmass is composed of a fine crystalline
aggregate of feldpsar and quartz.  Apatite, garnet, magnetite, pyrite and
zircon are accessories.