Name: Basalt
Type: rock
Class: Igneous
Subclass: Mafic
Particle Size: Fine
Sample No.: Basalt_H1
Owner: JHU
Wavelength Range: All
Origin: from Chimney Rock, Somerset County, New Jersey, via Ward'sScientific (Cat. No. W-36)
Collection Date: N/A
Description: The sample from which the powder was derived is greenish-black aphanitic rock.Particle size was 0-75 micrometers. Original ASTER Spectral Library name was jhu.becknic.rock.igneous.mafic.fine.basal1.spectrum.txt
Composition:

Petrographic Description:  Microphenocrysts of augite (some glomeropor-
phyritic) are set in a matrix of thin laths of labradorite, granular
clinopyroxene and dark, essentially opaque glass which is subordinate and
interstitial.  Some of the glass has been altered to a brown iron-rich
chlorite.  The modes gave 31% feldspar, 30% pyroxene, 31% groundmass, 
0.2% opaque and 7.8% miscellaneous (alteration products).

Microprobe Analysis:  The feldspar composition ranged from An67 to An74
(labradorite-bytownite); pyroxene phases probed were augite and pigeonite.

Chemical Analysis:
SiO2  51.02
CaO  11.26
TiO2  1.07
Na2O  1.77
Al2O3  14.02
K2O  0.40
Fe2O3  2.59
H2O  2.55
FeO  7.94
P2O5  0.12
MnO  0.17
MgO  7.86
TOTAL  100.77  (CO2 not analyzed)
