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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: Thenardite GDS146 DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: GDS146

MINERAL_TYPE: Sulfate

MINERAL: Thenardite

FORMULA: Na2SO4

FORMULA_HTML: Na2SO4

COLLECTION_LOCALITY: Saline Valley, California

ORIGINAL_DONOR: Jim Crowley

CURRENT_SAMPLE_LOCATION: USGS Reston, Virginia

ULTIMATE_SAMPLE_LOCATION: USGS Reston, Virginia

SAMPLE_DESCRIPTION:

Spectrum originally published in: Crowley, J.K., 1991, Visible and Near-Infrared (0.4 - 2.5µm) Reflectance Spectra of Playa Evaporite Minerals: Journal of Geophysical Research, vol 96, no.B10, p. 16,231-16,240.

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

40 kV - 30 mA, 6.5-9.5 keV
File: tnrdt146.out, -.mdi
References: JCPDS #37-1465, HS450.3B
Found: Thenardite, weak to very weak unidentified reflections at 3.57, 2.00, and 1.78 angstoms.

Comment: Well-crystallized phase, but not as well crystallized (pattern not as sharp) as HS450.3B

J.S. Huebner, J. Pickrell, T. Schaefer, written communication(USGS)

END_XRD_ANALYSIS.

COMPOSITIONAL_ANALYSIS_TYPE: None # XRF, EM(WDS), ICP(Trace), WChem

COMPOSITION_TRACE:

COMPOSITION_DISCUSSION:

Presence of features at 1.5 and 2.1 µm indicates the contamination of this sample. Ideally thenardite Na2SO4 should be anhydrous. The spectral features at these positions may be due to different mineral phases or partial hydration of this sample. G. Swayze.

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1c2_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 4739 0.2-3.0µm 200 g.s.=
LIB_SPECTRA: splib05a r 6521 0.2-3.0µm 200 g.s.=


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