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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: Jarosite_Thin_Film GDS243 DESCRIPT

DOCUMENTATION_FORMAT: MIXTURE

SAMPLE_ID: GDS243

MIXTURE_TYPE: Coating # Areal, Intimate, Coating, or Molecular

MIXTURE: Jarosite thin film on a thin section glass slide

FORMULA: K(Fe+3)3(SO4)2(OH)6

FORMULA_HTML: KFe+33(SO4)2(OH)6

COLLECTION_LOCALITY: Warner Mine, Hot Springs, Mineral County, Nevada

ORIGINAL_DONOR: National Museum of Natural History, Washington DC, USA

COLLECTION_LATITUDE: Not Available # degrees and decimal minutes (N or S)

COLLECTION_LONGITUDE: Not Available # degrees and decimal minutes (W or E)

DATUM: Not Available # coordinate datum

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

Fine grained Jarosite NMNH95074-1 was used. Fine-grained powder was mixed with water and an eye-dropper was used to deposit a thin coating on a microscope glass thin section. The sample was dried over night and them measured spectrally. Our goal was to unsaturate the jarosite bands and mimic the spectral absorptions found in natural jarosite coatings. Sample was prepared by Gregg Swayze.

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

Natrojarosite + quartz (minor).

END_XRD_ANALYSIS.

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

COMPOSITION_TRACE: None

COMPOSITION_DISCUSSION:

None

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

None

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

Spectrum has Fe-related absorptions characteristic of jarosite. Bands are located at 0.4367, 0.5060, and 0.9262 microns. Of note is the narrow width of the 0.9262 micron band: it is only 256 nm wide -- much narrower than in spectra of powdered jarosite samples. Apparently the band narrows most on the long wavelength side of this band in coatings.

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1b2_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: splib05a r 9186 0.2-3.0µm 200 g.s.=


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