Name: Picrite
Type: rock
Class: Igneous
Subclass: Ultramafic
Particle Size: Fine
Sample No.: Picrite_H2
Owner: JHU
Wavelength Range: All
Origin: from Kilauea, via Rosalind Helz, USGS, Reston, VA (Cat. No.79-5-180.8)
Collection Date: N/A
Description: Powder derived from sample that was light gray porphyritic, slightly vesicular rock.  Green olivine  phenocrysts range in size from approx. 0.5 mm to 4.0 mm and make up about 2-3% of the rock.  The grayish groundmass is very fine-grained.Particle size was 0-75 micrometers. Original ASTER Spectral Library name was jhu.becknic.rock.igneous.ultramafic.fine.picrit2.spectrum.txt
Composition:

Petrographic Description:  A porphyritic, fine grained rock with a felty 
texture consisting of olivine phenocrysts and groundmass phases of olivine,
augite, plagioclase, an orthopyroxene, opaques, some pseudo-brookite and
apatite, along with minor interstitial glass.  The glass analysis is given
below.

Microprobe Analysis:  (by Rosalind Helz).  Probe analysis indicated the
presence of two opaque phases; chromite and ilmenite.  The latter phase
contained 6% MgO by weight, as did the pseudobrookite, which is typical 
for high-MgO bulk composition basalts.  Glass composition was:

SiO2  68.90
Cr2O3  0.00
TiO2  1.70
CaO  1.17
Al2O3  14.81
Na2  3.40
FeO  2.72
K2O  4.79
MnO  0.02
P2O5  0.33
MgO  0.70
TOTAL  98.54

Chemical Analysis:  (by John Marinenko, USGS, Reston, VA.)
SiO2  46.23
CaO  8.68
TiO2  1.47
Na2O  1.37
Al2O3  9.83
K2O  0.30
Fe2O3  0.53
H2O  0.04
FeO  10.49
P2O5  0.15
MnO  0.17
Cr2O3  0.23
MgO  20.65
TOTAL  100.14
