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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: Calcite WS272 DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: WS272

MINERAL_TYPE: Carbonate

MINERAL: Calcite (Calcite group)

FORMULA: CaCO3

FORMULA_HTML: CaCO3

COLLECTION_LOCALITY: Tunguska, Siberia, USSR

ORIGINAL_DONOR: Wards Scientific

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

Forms series with Rhodochrosite. Trimorphous with Aragonite and Vaterite.

This sample was ground from a beautiful single crystal of type Iceland Spar. The single crystal appeared pure, and the visible-NIR spectrum appears pure.

See Clark, R.N., T.V.V. King, M. Klejwa, G. Swayze, and N. Vergo, 1990, High spectral resolution reflectance spectroscopy of minerals: J. Geophys Res. 12653-12680.

IMAGE_OF_SAMPLE:
Photo of sample

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

Calcite + small amount of "other" -- by Norma Vergo However, there is no "other" apparent in the single crystals or the ground sample. -- Roger N. Clark

END_XRD_ANALYSIS.

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

COMPOSITION_TRACE: None

COMPOSITION_DISCUSSION:

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

Bimodal grain size distribution:

population 1 450µm 85 vol%
population 2 15µm 15 vol%

avg. grain size of populations = 410µm

Pure sample from single crystal. Rhombic cleavage, twins, uniaxial, very high birefringence, fizzes readily in dilute HCl. Smaller grains adhere to larger grains covering 40-80% of larger grains cleavage surfaces.

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1a2a3a4a # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns