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(For further information on spectrsocopy, see:
http://speclab.cr.usgs.gov)
TITLE: Topaz Wigwam_Area_2_#12 DESCRIPT
DOCUMENTATION_FORMAT: MINERAL
SAMPLE_ID: Wigwam_Area_2_#12
MINERAL_TYPE: Nesosilicate
MINERAL: Topaz
FORMULA: Al2SiO4(F,OH)2
FORMULA_HTML: Al2SiO4(F,OH)2
COLLECTION_LOCALITY: Wigwam Creek, Colorado, #1
ORIGINAL_DONOR: Gene Foord
CURRENT_SAMPLE_LOCATION: Gene Foord, USGS
ULTIMATE_SAMPLE_LOCATION: Gene Foord, USGS
SAMPLE_DESCRIPTION:
Most of the (OH-) in topaz is generally replaced by F-, the maximum fluorine content being 20.7%.
Hurlbut, C.S., and C. Klein, 1977, Manual of Mineralogy, 19th Ed. John Wiley and Sons, New York, New York, 353p.
Topaz is commonly found as a vapor phase or hydrothermal crystallization product in three principal geologic associations: rhyolites; pegmatities and greisens; and hydrothermal veins. The mineral also occurs as a liquidus phase in ongonites and some rhyolites.
Foord, E.L., L. Jackson, J. Taggart, J. Crock, and T.V.V. King, 1988, Environment of Crystallization of Topaz as Determined From Crystal Chemistry and Infrared Spectra. Program and Abstracts Annual GSA Meeting, October 31-November 3, 1988, Denver CO, A224,#4128.
END_SAMPLE_DESCRIPTION.
XRD_ANALYSIS:
Not Available
END_XRD_ANALYSIS.
COMPOSITIONAL_ANALYSIS_TYPE: None # XRF, EM(WDS), ICP(Trace), WChem
COMPOSITION_TRACE:
COMPOSITION_DISCUSSION:
H2O- = 0.02, H2O+= 0.34
Compositions of the 65 topaz samples are distincly grouped in terms of H2O+, F, and trace element content. H2O+ contents for (in wt. %) for rhyolitic topaz ranged from 0.06 to 0.11, pegmatitic topaz from 0.20 to 0.91, and hydrothermal topaz from 1.69 to 2.67; fluorine content is inversely related to water content. This is a pegmatitic topaz.
Foord, E.L., L. Jackson, J. Taggart, J. Crock, and T.V.V. King, 1988, Environment of Crystallization of Topaz as Determined From Crystal Chemistry and Infrared Spectra. Program and Abstracts Annual GSA Meeting, October 31-November 3, 1988, Denver CO, A224,#4128.
END_COMPOSITION_DISCUSSION.
MICROSCOPIC_EXAMINATION:
END_MICROSCOPIC_EXAMINATION.
SPECTROSCOPIC_DISCUSSION:
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: | splib04a r 4826 | 0.2-3.0µm | 200 | g.s.= |
| LIB_SPECTRA: | splib05a r 6800 | 0.2-3.0µm | 200 | g.s.= |
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