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USGS Spectral Library Version 7 Sample Description

Kokaly, R.F., Clark, R.N., Swayze, G.A., Livo, K.E., Hoefen, T.M., Pearson, N.C., Wise, R.A., Benzel, W.M., Lowers, H.A., Driscoll, R.L., and Klein, A.J., 2017, USGS Spectral Library Version 7: U.S. Geological Survey Data Series 1035, 61 p., https://doi.org/10.3133/ds1035
For more information on the library, see: local link web link

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
Nicolet measurement was made of a sample split that was ground for XRD measurement.

IMAGE_OF_SAMPLE:
NO PHOTO

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

Quartz, from Steve Sutley, written communication, 1992

END_XRD_ANALYSIS.

COMPOSITIONAL_ANALYSIS_TYPE: None # XRF, EPMA, 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history of the Cuprite Mining District, southwestern Nevada: an integrated geological and geophysical approach: unpublished Ph.D. Dissertation, University of Colorado at Boulder, 399p.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: 1a2a3a4_ # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns