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Clark et. al. 2003 USGS Open File Report 03-395
Spectral Library splib05a Sample Description

(For further information on spectrsocopy, see: http://speclab.cr.usgs.gov)

TITLE: Hypersthene NMNHC2368 DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: NMNHC2368

MINERAL_TYPE: Inosilicate

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

FORMULA: (Mg,Fe+2)2Si2O6

FORMULA_HTML: (Mg,Fe+2)Si2O6

COLLECTION_LOCALITY: Western Greenland

ORIGINAL_DONOR: National Museum of Natural History

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

Enstatite-orthoferrosilite series member.

"Results of petrographic examination: One piece and one small fragment weighing 21.59 g. Part of single crystal; black. Very small amount of surface contamination which may be removed by scratching. Also some quartz inclusions which may be possible to break free. Under the microscope it is green-brown pleochroic with a relatively high index of refraction. It appears mildly altered with some (2%) iron-stained opaque material present."

Salisbury, J. W., Walter, L. W., and Vergo, N., 1987, Mid-Infrared (2.1-25µm) Spectra of Minerals: First Edition, U.S. Geological Survey Open File Report 87-263.

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

This sample contains hypersthene plus a small amount of talc and some other minerals (small amount). No clinopyroxene exsolution seen. (Norma Vergo)

"This sample is predominantly hypersthene with a small amount of talc and a small amount of other mineral(s). However, the amount of talc appears insufficient to affect the infrared spectrum, because even the strong hydroxyl bands of talc between 3600 and 4600 cm-1, which are extremely prominent in the spectrum of the 0-74 µ size range of talc, are not obvious in the spectrum of the 0-74 µm size range of hypersthene."

Salisbury, J. W., Walter, L. W., and Vergo, N., 1987, Mid-Infrared (2.1-25µm) Spectra of Minerals: First Edition, U.S. Geological Survey Open File Report 87-263.

END_XRD_ANALYSIS.

COMPOSITIONAL_ANALYSIS_TYPE: EM # XRF, EM(WDS), ICP(Trace), WChem


COMPOSITION
KEYWORD
Oxide
ASCII
Amount Weight
Percent, %
Oxide
html
COMPOSITION: SiO2 51.32 wt% SiO2
COMPOSITION: TiO2 0.29 wt% TiO2
COMPOSITION: Al2O3 4.89 wt% Al2O3
COMPOSITION: FeO 17.07 wt% FeO
COMPOSITION: MnO 0.35 wt% MnO
COMPOSITION: MgO 26.09 wt% MgO
COMPOSITION: CaO 1.27 wt% CaO
COMPOSITION: Na2O 0.05 wt% Na2O
COMPOSITION: K2O 0.02 wt% K2O
COMPOSITION: Total 101.33 wt%
COMPOSITION: O=Cl,F,S wt% #correction for Cl, F, S
COMPOSITION: New Total wt%

COMPOSITION_TRACE:

None

COMPOSITION_DISCUSSION:

"Microprobe analysis indicates exsolution of a small amount of clinopyroxene as shown by presence of Ca and concomitment loss of magnesium and iron for 2 out of 20 analyses."

Salisbury, J. W., Walter, L. W., and Vergo, N., 1987, Mid-Infrared (2.1-25µm) Spectra of Minerals: First Edition, U.S. Geological Survey Open File Report 87-263.

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

Not done yet

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1b2_3_4_ # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns

LIB_SPECTRA_HED: where Wave Range Av_Rs_Pwr Comment
LIB_SPECTRA: splib04a r 2251 0.2-3.0µm 200 g.s.=
LIB_SPECTRA: splib05a r 3416 0.2-3.0µm 200 g.s.=


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