Name: Norite
Type: rock
Class: Igneous
Subclass: Mafic
Particle Size: Solid
Sample No.: Norite_H2
Owner: JHU
Wavelength Range: All
Origin: from Nye, Montana, via Ward's Scientific (Cat. No. W-40)
Collection Date: N/A
Description: A dark greenish-gray, medium-grained granular rock composed of olivine, pyroxene, plagioclase laths (< 3 mm), opaques, and a few bronze colored mica grains (phlogopite?). Original ASTER Spectral Library name was jhu.becknic.rock.igneous.mafic.solid.norite2.spectrum.txt
Composition:

Petrographic Description:  An equigranular rock with subophitic texture
consisting of subhedral plagioclase laths (38%), occasionally showing either
oscillatory or normal zoning, partially enclosed in orthopyroxene (approx. 
27%) or clinopyroxene (11%) anhedra.  There are scattered olivine grains 
(approx. 4%) which are crisscrossed with brownish serpentine veinlets.  
Some areas of the sample are heavily sericitized.  Very minor amounts (< 
1%) of biotite are alsopresent.  Called a "pryoxenite" by Ward's, but contains 
too much plagioclase.

Microprobe Analysis:  Microprobe analysis shows that the orthopyroxene 
phase was hypersthene, while that of the clinopyroxene was iron-rich 
diopside (salite).  The feldspars probed were labradorite, the mica was 
phlogopite and an opaque proved to be ilmenite with about 0.6% each of 
MgO and MnO.

Chemical Analysis:
SiO2  48.23
CaO  6.43
TiO2  1.1
Na2O  1.85
Al2O3  12.31
K2O  0.74
Fe2O3  2.36
H2O  3.16
FeO  10.78
P2O5  0.06
MnO  0.22
MgO  12.95
TOTAL  100.19
