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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: Chalcedony CU91-6A DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: CU91-6A

MINERAL_TYPE: Tectosilicate

MINERAL: Chalcedony (var. of Quartz)

FORMULA: SiO2

FORMULA_HTML: SiO2

COLLECTION_LOCALITY: Cuprite, Nevada

ORIGINAL_DONOR: Greg Swayze

COLLECTION_LATITUDE: N37 32.43' # degrees and decimal minutes (N or S)

COLLECTION_LONGITUDE: W117 10.25' # degrees and decimal minutes (W or E) P> DATUM: NAD27 # coordinate datum

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

SEM analyses shows crystal morphology indicative of chalcedony. G. Swayze

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

Quartz, from Steve Sutley, written communication, 1992

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 absorptions characteristic of chalcedony with a strong OH fist overtone band at 1.4211 microns, a structual water band at 1.9193 microns, and a Si-OH combination band at 2.2164 microns. The 1.4211 micron band lacks a shoulder on the long wavelength side of the absorption indicating that this sample does not contain detectable amounts of opal.

See: Swayze, G.A., 1997, The hydrothermal and structural history of the Cuprite Mining District, southwestern Nevada: an integrated geological and geophysical approach: unpublished Ph.D. Dissertation, University of Colorado at Boulder, 399p.

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 894 0.2-3.0µm 200 g.s.=
LIB_SPECTRA: splib05a r 1602 0.2-3.0µm 200 g.s.=


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