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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 PYX02 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: 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 tremolite. The tremoilte
shows in the spectra as weak (narrow) bands at 2.3 m and 1.4 m. Singer suspected the tremolite,
but it is confirmed by higher resolution spectra in this library.

The sample was ground and wet sieved in methanol at the USGS Denver Spectroscopy Laboratory by Roger Clark. Sieve intervals are: 5-10 Ám (g)
10-20 Ám (a)
20-30 Ám (d)
30-45 Ám (e)
45-104 Ám (f)
104-150 Ám (b)
150-250 Ám (c)
>250 Ám (h)

SEM photos were done by R. Clark on each sieve interval to characterize the grain sizes. Letter denotes spectrum designation.

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: 1c2_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 2263 0.2-3.0µm 200 g.s.=350 µm
LIB_SPECTRA: splib04a r 2274 0.2-3.0µm 200 g.s.=180 µm
LIB_SPECTRA: splib04a r 2285 0.2-3.0µm 200 g.s.=120 µm
LIB_SPECTRA: splib04a r 2296 0.2-3.0µm 200 g.s.=60 µm
LIB_SPECTRA: splib04a r 2308 0.2-3.0µm 200 g.s.=34 µm
LIB_SPECTRA: splib04a r 2319 0.2-3.0µm 200 g.s.=23 µm
LIB_SPECTRA: splib04a r 2330 0.2-3.0µm 200 g.s.=12 µm
LIB_SPECTRA: splib04a r 2341 0.2-3.0µm 200 g.s.= 7 µm
LIB_SPECTRA: splib05a r 3431 0.2-3.0µm 200 g.s.=350 µm
LIB_SPECTRA: splib05a r 3445 0.2-3.0µm 200 g.s.=180 µm
LIB_SPECTRA: splib05a r 3459 0.2-3.0µm 200 g.s.=120 µm
LIB_SPECTRA: splib05a r 3473 0.2-3.0µm 200 g.s.=60 µm
LIB_SPECTRA: splib05a r 3487 0.2-3.0µm 200 g.s.=34 µm
LIB_SPECTRA: splib05a r 3501 0.2-3.0µm 200 g.s.=23 µm
LIB_SPECTRA: splib05a r 3516 0.2-3.0µm 200 g.s.=12 µm
LIB_SPECTRA: splib05a r 3530 0.2-3.0µm 200 g.s.= 7 µm


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