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: Wollastonite HS348 DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: HS348.1B, HS348.2B, HS348.3B, HS348.4B

MINERAL_TYPE: Inosilicate

MINERAL: Wollastonite

FORMULA: CaSiO3

FORMULA_HTML: CaSiO₃

COLLECTION_LOCALITY: Santa Fe Mine, Pichucalco, Chiapas, Mexico

ORIGINAL_DONOR: Hunt and Salisbury Collection

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

"Results of petrographic examination: Single crystal 2 x 0.5 x 1 cm and one large piece 4 x 0.5 x 1. cm. One dirty surface and sulfide inclusions which were separated by crushing and hand picking. Under petrographic microscope, some grains show a little alteration and inclusions or voids along cleavage directions - possible exsolved 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.

Grain size fractions are indicated by the extension after the sample number:
.1B = <5 µm
.2B = <74 µm
.3B = 74-250 µm
.4B = 250-1200 µm

IMAGE_OF_SAMPLE:

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

X-ray analysis indicates sample is pure.

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 50.84 wt% SiO₂

COMPOSITION: TiO2 0.01 wt% TiO₂

COMPOSITION: Al2O3 0.05 wt% Al₂O₃

COMPOSITION: FeO 0.18 wt% FeO

COMPOSITION: MnO 0.75 wt% MnO

COMPOSITION: MgO 0.08 wt% MgO

COMPOSITION: CaO 47.62 wt% CaO

COMPOSITION: Na2O 0.01 wt% Na₂O

COMPOSITION: K2O 0.03 wt% K₂O

COMPOSITION: Total 99.57 wt%

COMPOSITION KEYWORD	Oxide ASCII	Amount	Weight Percent, %	Oxide html
COMPOSITION:	SiO2	50.84	wt%	SiO₂
COMPOSITION:	TiO2	0.01	wt%	TiO₂
COMPOSITION:	Al2O3	0.05	wt%	Al₂O₃
COMPOSITION:	FeO	0.18	wt%	FeO
COMPOSITION:	MnO	0.75	wt%	MnO
COMPOSITION:	MgO	0.08	wt%	MgO
COMPOSITION:	CaO	47.62	wt%	CaO
COMPOSITION:	Na2O	0.01	wt%	Na₂O
COMPOSITION:	K2O	0.03	wt%	K₂O
COMPOSITION:	Total	99.57	wt%

COMPOSITION_TRACE:

COMPOSITION_DISCUSSION:

Microprobe analysis shows that sample is homogeneous between and within grains. Average of 7 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:

Colorless transparent to white. Almost no contamination visually apparent. Insignificant number of crystals with small (1/50th the size of the wollastonite crystal) embedded dark grains.

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

Presence of a sharp 1.4 and broad 2.26 micron absorptions suggest a hydroxyl bearing contaminant. Also the broad electonic absorption centered at 1.38 microns may be from the sulfide inclusions.

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1c2_3_4_ # HS348.1B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2_3_4_ # HS348.2B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2c3c4c # HS348.3B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1b2_3_4_ # HS348.4B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns