Sample Description USGS Spectral Library Version 7

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
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TITLE: Quartz GDS31 DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: GDS31 0-74um fr

MINERAL_TYPE: Tectosilicate

MINERAL: Quartz

FORMULA: SiO2

FORMULA_HTML: SiO₂

COLLECTION_LOCALITY: Brazil

ORIGINAL_DONOR: Bruce Hemingway

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

Polymorphous with Tridymite, Cristobalite, Coesite and Stishovite.

Quartz (Si0₂) is an important constituent of igneous rocks which have an excess of silica, such as granite, rhyolite or pegmatite. Because it is extremely resistant to both mechanical and chemical attack, it usually survives the weathering process. Quartz is an extremely difficult mineral to grind without contamination, because of its hardness.

"Results of petrographic examination: Hand sample appears entirely pure, being a clear and transparent fragment of a single crystal. Under petrographic microscope, sample also pure and clear."

Salisbury, J. W., Walter, L. W., and Vergo, N., 1987, Mid-Infrared (2.1-25µm) Spectra of Minerals: First Edition, U.S. Geological Survey Open File Report 87-263.

IMAGE_OF_SAMPLE:
NO PHOTO

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

Pure quartz. (Jack Salisbury)
Pure quartz. (Norma Vergo)

END_XRD_ANALYSIS.

COMPOSITIONAL_ANALYSIS_TYPE: None # XRF, EPMA, ICP(Trace), WChem

COMPOSITION_TRACE:

COMPOSITION_DISCUSSION:

Results of XRF or other compositional analysis: Essentially pure SiO₂ within the limits of microprobe error.

Salisbury, J. W., Walter, L. W., and Vergo, N., 1987, Mid-Infrared (2.1-25µm) Spectra of Minerals: First Edition, U.S. Geological Survey Open File Report 87-263.

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

Colorless transparent. No contamination visually apparent.

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1a2_3_4_ # GDS31 0-74um fr # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns