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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: Elbaite NMNH94217-1 DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: NMNH94217-1.a, NMNH94217-1.b, NMNH94217-1.c

MINERAL_TYPE: Cyclosilicate

MINERAL: Elbaite (Tourmaline group)

FORMULA: Na(Li,Al)3Al6(BO3)3Si6O18(OH)4

FORMULA_HTML: Na(Li,Al)3Al6(BO3)3Si6O18(OH)4

COLLECTION_LOCALITY: Sao Jose De Brejuada, Minas Gerais, Brazil

ORIGINAL_DONOR: National Museum of Natural History (Smithsonian)

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

Forms series with Dravite.

"Results of petrographic examination: A purple sudhedral crystal, transparent with some green coloration to one end. Sample is ~5mm x 2cm x 2cm. Under petrographic microscope, sample appears pure, clear."

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 the following sieve intervals: (a) 250µm, (b) 150µm, (c) less than 74µm

IMAGE_OF_SAMPLE:
Photo of sample

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

Elbaite plus many peaks (Norma Vergo).

END_XRD_ANALYSIS.

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


COMPOSITION
KEYWORD
Oxide
ASCII
Amount Weight
Percent, %
Oxide
html
COMPOSITION: SiO2 36.83 wt% SiO2
COMPOSITION: TiO2 0.04 wt% TiO2
COMPOSITION: Al2O3 40.56 wt% Al2O3
COMPOSITION: FeO 0.12 wt% FeO
COMPOSITION: MnO 4.40 wt% MnO
COMPOSITION: MgO 0.03 wt% MgO
COMPOSITION: CaO 0.13 wt% CaO
COMPOSITION: Na2O 2.37 wt% Na2O
COMPOSITION: K2O 0.01 wt% K2O
COMPOSITION: Total 84.49 wt%
COMPOSITION: O=Cl,F,S wt% #correction for Cl, F, S
COMPOSITION: New Total wt%

COMPOSITION_TRACE: None

COMPOSITION_DISCUSSION:

Microprobe analysis showed the sample to be homogeneous within and between grains. Average of seven analyses does not include lithium, boron or water, but demonstrates the presence of sufficient manganese to indicate that this is not end member elbaite.

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:

Grain Size distributions:
250 µm fraction: bimodal gr sz dist.
population 1 avg. grain size size = 662 µm 99 vol%
population 2 avg. grain size size = 10 µm 1 vol%
avg. grain size entire population = 659 µm

74 < x < 250 µm fraction: avg. grain size = 196 µm

< 74 µm fraction: bimodal gr sz dist.
population 1 avg. grain size = 68 µm 75 vol%
population 2 avg. grain size = 15 µm 25 vol%
avg. grain size entire population = 59 µm

Samples are very pure. No cleavage, uniaxial (+), slight pink color. All consistent with tourmaline. M. Cowoski and G. Swayze.

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1b2b3b4b # Elbaite NMNH94217-1.a # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1b2b3b4b # Elbaite NMNH94217-1.b # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1b2_3_4_ # Elbaite NMNH94217-1.c # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns