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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: Anorthite GDS28 <250um DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: GDS28

MINERAL_TYPE: Tectosilicate

MINERAL: Anorthite (Plagioclase, Ca end member, Feldspar group)

FORMULA: CaAl2Si2O8

FORMULA_HTML: CaAl2Si2O8

COLLECTION_LOCALITY: Synthetic

ORIGINAL_DONOR: Bruce Hemingway, U.S.G.S.

CURRENT_SAMPLE_LOCATION: USGS Reston, VA.

ULTIMATE_SAMPLE_LOCATION: USGS Reston, VA.

SAMPLE_DESCRIPTION:

The original sample and mid-IR spectrum was described in:

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.

From that study, the sample was described as pure.

IMAGE_OF_SAMPLE:
Photo of sample

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

Pure Anorthite.

END_XRD_ANALYSIS.

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


COMPOSITION
KEYWORD
Oxide
ASCII
Amount Weight
Percent, %
Oxide
html
COMPOSITION: SiO2 43.53 wt% SiO2
COMPOSITION: TiO2 0.01 wt% TiO2
COMPOSITION: Al2O3 37.36 wt% Al2O3
COMPOSITION: FeO 0.02 wt% FeO
COMPOSITION: MnO 0.03 wt% MnO
COMPOSITION: MgO 0.03 wt% MgO
COMPOSITION: CaO 19.26 wt% CaO
COMPOSITION: Na2O 0.03 wt% Na2O
COMPOSITION: K2O 0.04 wt% K2O
COMPOSITION: Total 100.32 wt%
COMPOSITION: O=Cl,F,S wt% #correction for Cl, F, S
COMPOSITION: New Total 100.32 wt%

COMPOSITION_TRACE: None

COMPOSITION_DISCUSSION:

Microprobe analysis is the average of 10 analyses. See also: Robie, R.A., Hemingway, B.S., and Wilson, W.H., 1978, American Min., v.63, p. 9-123.

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

The sample appears to be pure anorthite with very fine (cryptocrystalline) texture according to:

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. avg. grain size = 200um

Abundant vapor bubbles or fluid inclusions, elongate grains sometimes sided by cleavage planes. G. Swayze

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1a2a3a4_ # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns