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.

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, EM(WDS), 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%

av gr sz 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: 1_2_3_4_

LIB_SPECTRA_HED: where Wave Range Av_Rs_Pwr Comment

LIB_SPECTRA: splib04a r 787 0.2-3.0µm 200 g.s.= 410 µm

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

LIB_SPECTRA: splib06a r ____ 1.5-25µm 250 g.s.=