Name: Granite
Type: rock
Class: Igneous
Subclass: Felsic
Particle Size: Fine
Sample No.: Granite_H2
Owner: JHU
Wavelength Range: All
Origin: From Santa Rita Mountains, Arizona via Smithsonian (Cat. No.NMNH 113640-17)
Collection Date: N/A
Description: Powder derived from a gray, medium-grained rock consisting of white feldspar grains, some of which contain red or pinkish cores, quartz, and minor biotite.  Some of the feldspar appears to be perthitic.Particle size was 0-75 micrometers Original ASTER Spectral Library name was jhu.becknic.rock.igneous.felsic.fine.granit2.spectrum.txt
Composition:

Petrographic Description:  Typically these rocks are hypidiomorphic with 
granular texture.  Quartz, orthoclase, and plagioclase make up at least 93% 
of the rocks.  Quartz anhedra possess moderate to strong undulatory 
extinction, the orthoclase anhedra are slightly kaolinitized.  Perthite is 
common in the orthoclase with the amount of albite in the orthoclase is 
approx. 8%.  The plagioclase is often sericitized, while the biotite is largely 
altered to chlorite.  The modes for this sample were; 40.4% orthoclase, 
38.5% quartz, 19.7% plagioclase, 1.1% biotite, and 0.3% magnetite.  There 
was no sign of carbonate in thin section, but spectrum and chemical analysis 
both indicate presence of a small amount.

Microprobe Analysis:  The analysis revealed the plagioclase composition to 
be albite, with no more than 5% anorthite.

Chemical Analysis:
SiO2  75.50
CaO  0.35
TiO2  0.21
Na2O  3.5
Al2O3  12.6
K2O  4.7
Fe2O3  1.0
H2O  1.04
FeO  0.24
P2O5  0.02
MnO  0.02
CO2  0.15
MgO  0.23
TOTAL  99.56
