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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: Alunite-K GDS84 Na03 DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: GDS84

MINERAL_TYPE: Sulfate

MINERAL: Alunite (Alunite Group)

FORMULA: KAl3(SO4)2(OH)6

FORMULA_HTML: KAl3(SO4)2(OH)6

COLLECTION_LOCALITY: Marysvale, Utah, USA

ORIGINAL_DONOR: Roger Stoffregen

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

Coarse vein alunite from Marysvale hydrothermal deposit.

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

GDS84 K-alunite 40 kV - 30 mA, 6.5-9.5 keV File: kalnt84.out, *.mdi (smear mount on quartz plate) References: JCPDS #14-136; GDS-97B Found: Alunite Comment- Moderately sharp reflections; the (003)-(101) doublet is poorly resolved, in contrast to GDS-97B. There may be compositional heterogeneity. Weak to very weak reflections do not appear on the JCPDS card; they could be alunite reflections, or they could be caused by trace quantities of impurities. Lattice spacing's are smaller than those that JCPDS #14-136 report for an alunite from the same locality, Marysvale, Utah.

see: Stoffregen, R.E., and C.N. Alpers, Observations on the unit-cell dimensions, H2O contents, and delD values of natural and synthetic alunite, American Mineralogist, 77, 1092-1098, 1992.

END_XRD_ANALYSIS.

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

COMPOSITION_TRACE: None

COMPOSITION_DISCUSSION:

Sample has 3 mole % Na and 97 mole % K from atomic absorption analysis. Stoffregen, R., and Alpers, C., 1992, Observations on the unit-cell dimensions, H2O contents and del D values of natural and synthetic alunite: American Mineralogist, v.77, p. 1092-1098.

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

Sample has relatively strong vibrational features between 1.4 - 1.5, 1.77, and 2.0 - 2.24, 2.32, and a complex centered at 2.5 microns.

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 204 0.2-3.0µm 200 g.s.= 260µm
LIB_SPECTRA: splib05a r 386 0.2-3.0µm 200 g.s.=
LIB_SPECTRA: splib05a r 398 1.3-5.3µm 200 g.s.=


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