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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: Elbaite NMNH94217-1 DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: NMNH94217

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 seive intervals: (a) 250µm, (b) 150µm, (c) less than 74µm

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

Elbaite plus many peaks (Norma Vergo).

END_XRD_ANALYSIS.

COMPOSITIONAL_ANALYSIS_TYPE: EM(WDS) # XRF, EM(WDS), 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: 1a2_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 1495 0.2-3.0µm 200 g.s.= 659 µm
LIB_SPECTRA: splib04a r 1507 0.2-3.0µm 200 g.s.= 196 µm
LIB_SPECTRA: splib04a r 1519 0.2-3.0µm 200 g.s.= 59 µm
LIB_SPECTRA: splib05a r 2509 0.2-3.0µm 200 g.s.=
LIB_SPECTRA: splib05a r 2523 0.2-3.0µm 200 g.s.=
LIB_SPECTRA: splib05a r 2537 0.2-3.0µm 200 g.s.=


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