Sample Description USGS Spectral Library Version 7

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
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TITLE: Olivine NMNH137044 DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: NMNH137044.a, NMNH137044.b

MINERAL_TYPE: Nesosilicate

MINERAL: Olivine (Fosterite-Fayalite series, Olivine group)

FORMULA: (Mg,Fe)2SiO4 Fo92

FORMULA_HTML: (Mg,Fe)₂SiO₄ Fo₉₂

COLLECTION_LOCALITY: Chavira Mine, Kamargo (nr), Chihuahua, Mexico

ORIGINAL_DONOR: Smithsonian

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

The sample consists of many 0.5cm particles plus one large fragment. Under petrographic microscope, the hand-picked sample appears clean but one of the grains may be pyroxene.

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.

Sample is in two sieve intervals: (a) 74-250µm and (b) less than 74µm.

IMAGE_OF_SAMPLE:

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

Pure forsterite.

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: EPMA # XRF, EPMA, ICP(Trace), WChem

COMPOSITION
KEYWORD Oxide
ASCII Amount Weight
Percent, % Oxide
html

COMPOSITION: SiO2 40.27 wt% SiO₂

COMPOSITION: TiO2 0.01 wt% TiO₂

COMPOSITION: Al2O3 0.02 wt% Al₂O₃

COMPOSITION: FeO 8.70 wt% FeO

COMPOSITION: MnO 0.15 wt% MnO

COMPOSITION: MgO 52.28 wt% MgO

COMPOSITION: CaO 0.06 wt% CaO

COMPOSITION: Na2O 0.02 wt% Na₂O

COMPOSITION: K2O 0.01 wt% K₂O

COMPOSITION: Total 101.52 wt%

COMPOSITION KEYWORD	Oxide ASCII	Amount	Weight Percent, %	Oxide html
COMPOSITION:	SiO2	40.27	wt%	SiO₂
COMPOSITION:	TiO2	0.01	wt%	TiO₂
COMPOSITION:	Al2O3	0.02	wt%	Al₂O₃
COMPOSITION:	FeO	8.70	wt%	FeO
COMPOSITION:	MnO	0.15	wt%	MnO
COMPOSITION:	MgO	52.28	wt%	MgO
COMPOSITION:	CaO	0.06	wt%	CaO
COMPOSITION:	Na2O	0.02	wt%	Na₂O
COMPOSITION:	K2O	0.01	wt%	K₂O
COMPOSITION:	Total	101.52	wt%

COMPOSITION_TRACE:

COMPOSITION_DISCUSSION:

Microprobe analysis of hand-picked grains showed the sample to be homogeneous within and between grains. Average of 10 analyses showed the sum of the divalent cations too high, but Fo content is approximately 92 mole percent.

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:

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1a2_3_4_ # NMNH137044.a # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1a2_3_4_ # NMNH137044.b # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns