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USGS Spectral Library Version 7 Sample Description

Kokaly, R.F., Clark, R.N., Swayze, G.A., Livo, K.E., Hoefen, T.M., Pearson, N.C., Wise, R.A., Benzel, W.M., Lowers, H.A., Driscoll, R.L., and Klein, A.J., 2017, USGS Spectral Library Version 7: U.S. Geological Survey Data Series 1035, 61 p., https://doi.org/10.3133/ds1035
For more information on the library, see: local link web link

TITLE: Hypersthene PYX02 DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: PYX02.a, PYX02.b, PYX02.c, PYX02.d, PYX02.e, PYX02.f, PYX02.g, PYX02.h

MINERAL_TYPE: Inosilicate

MINERAL: Hypersthene (Fe-rich enstatite, Pyroxene group)

FORMULA: (Mg,Fe+2)2Si2O6

FORMULA_HTML: (Mg,Fe+2)Si2O6

COLLECTION_LOCALITY: Bamble, Norway

ORIGINAL_DONOR: Wards Scientific, and Robert B. Singer

CURRENT_SAMPLE_LOCATION: U.S.G.S. Denver Spectroscopy Laboratory.

ULTIMATE_SAMPLE_LOCATION: U.S.G.S. Denver Spectroscopy Laboratory.

SAMPLE_DESCRIPTION:

Intermediate member of the series Enstatite-Orthoferrosilite. The original sample description and vis-nir spectrum was published by:
Singer, R.B., 1981, Near-Infrared spectral reflectance of mineral mixtures: Systematic combinations of pyroxenes, olivine, and iron oxides: J. Geophys Res., v. 86, p. 7967-7982.
The sample is pure pyroxene except for a small (less than 2%?) amount of amphibole (possibly tremolite). The amphibole absorption features appear in the spectra as weak, narrow bands at 2.3 m and 1.4 m. Singer suspected the tremolite contamination and the amphibole features are in the higher resolution spectra in this library support that.

The sample was ground and wet sieved in methanol at the USGS Denver Spectroscopy Laboratory by Roger Clark. SEM photos were done by R. Clark on each sieve interval to characterize the grain sizes.

Grain size fractions are indicated by the extension after the sample number:
.g = 5-10 microns
.a = 10-20 microns
.d = 20-30 microns
.e = 30-45 microns
.f = 45-104 microns
.b = 104-150 microns
.c = 150-250 microns
.h = >250 microns

IMAGE_OF_SAMPLE:
NO PHOTO

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

None

END_XRD_ANALYSIS.

COMPOSITIONAL_ANALYSIS_TYPE: XRF


COMPOSITION
KEYWORD
Oxide
ASCII
Amount Weight
Percent, %
Oxide
html
COMPOSITION: SiO2 55.30 wt% SiO2
COMPOSITION: TiO2 0.05 wt% TiO2
COMPOSITION: Al2O3 0.12 wt% Al2O3
COMPOSITION: Fe2O3 (as FeO)wt% Fe2O3
COMPOSITION: FeO 9.38 wt% FeO
COMPOSITION: MnO 0.15 wt% MnO
COMPOSITION: MgO 32.80 wt% MgO
COMPOSITION: Na2O 0.00 wt% Na2O
COMPOSITION: P2O5 0.01 wt% P2O5
COMPOSITION: LOI 2.00 wt% LOI
COMPOSITION: Total 100.28 wt%
COMPOSITION: O=Cl,F,S wt% #correction for Cl, F, S
COMPOSITION: New Total 100.28 wt%

COMPOSITION_TRACE:

None

COMPOSITION_DISCUSSION:

The compositional analysis is from: Singer, R.B., 1981, Near-Infrared spectral reflectance of mineral mixtures: Systematic combinations of pyroxenes, olivine, and iron oxides: J. Geophys Res., v. 86, p. 7967-7982.

All Fe2O3 is reported in the FeO amount. The analysis was performed by XRA Laboratory, Ontario Canada. FeO was by wet chemistry, all else by XRF.

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

The sample appears to be pure pyroxene except for a small (less than ~ 2%) amount of tremolite.

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1c2c3b4b # Hypersthene PYX02.a # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2c3b4b # Hypersthene PYX02.b # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2c3b4b # Hypersthene PYX02.c # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2c3b4b # Hypersthene PYX02.d # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2c3b4b # Hypersthene PYX02.e # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2c3b4b # Hypersthene PYX02.f # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2c3b4b # Hypersthene PYX02.g # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2c3b4b # Hypersthene PYX02.h # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns