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(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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