Composition:

Petrographic Description:  The modes for phenocrysts for this sample gave
26.75% plagioclase, 8.5% augite, 1.05% magnetite, 0.95% hypersthene, and
62.75% groundmass.  The groundmass for these samples consists of 
labradorite, augite, hypersthene, magnetite, ilmenite, trydimite as isolated grains and aggregates of small wedge-shaped crystals closely associated with small patches of intergrown granular quartz and chalcedony, anorthoclase, and  partly devitrified glass.

Microprobe Analysis:  The composition of the plagioclase phenocrysts was 
found to range from An59 to An62 (labradorite), while the composition in the groundmass ranged from An50 to An55.  The augite phenocryst composition was Wo 34%, En 43%, Fs 23%, that of the hypersthene phenocrysts was En 67%, Fs 33%.  Augite in the groundmass was W0 24%, En 45%, Fs 31%.

Chemical Analysis:
SiO2  57.20
CaO  8.85
TiO2  0.54
Na2O  2.50
Al2O3  16.35
K2O  0.68
Fe2O3  2.23
H2O  0.90
FeO  5.93
P2O5  0.36
MnO  0.14
MgO  4.65
TOTAL  100.3
