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: Vermiculite GDS906 expanded DESCRIPT

DOCUMENTATION_FORMAT: Man_Made

SAMPLE_ID: GDS906

MATERIAL_TYPE: Expanded Phyllosilicates

MATERIAL: Expanded Vermiculite Ore

FORMULA: (Mg,Fe2+,Al)3(Si,Al)4O10(OH)2.4H2O

FORMULA_HTML: (Mg,Fe²⁺,Al)₃(Si,Al)₄O₁₀(OH)₂^.4H₂O

COLLECTION_LOCALITY: This sample came from a bag of A-Tops® attic insulation from Beaver Falls, Pennsylvania and was supplied by the U.S. EPA in 2005.

ORIGINAL_DONOR: U.S. EPA

CURRENT_SAMPLE_LOCATION: USGS Denver, CO

ULTIMATE_SAMPLE_LOCATION: USGS Denver, CO

SAMPLE_DESCRIPTION:

The sample has a mottled golden color and ranges in grain size from 3 – 12 mm with an average around 7 mm (Fig. GDS906.photo.1).

A modified Cincinnati floation method was carried out on this sample. The sink fraction consists of mica flakes and small particles that were mounted on a stub for SEM examination.

The sample has a spectral signature similar to that of expanded vermiculite ore from the Palabora Mine, Phalaborwa, South Africa.

Original spectrum published in:

IMAGE_OF_SAMPLE:

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

No XRD analysis is available for this sample.

END_XRD_ANALYSIS.

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

COMPOSITION_TRACE: None

COMPOSITION_DISCUSSION:

The sample was examined with probe microanalysis. Spot analyses plot in the Palabora field on the Al/Ti versus Al/[Mg/(Mg+Fe)] diagram (Fig. GDS906.microprobe.1).

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

The sample was examined with SEM and Energy dispersive spectroscopy. Particles from the sink fraction were placed on an SEM stub, which was coated with carbon, and examined under high magnification (Figs. GDS906.EDS.1 to 4 and GDS906.SEM.1 and 2). No amphibole, talc, or serpentine grains were found.

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

The spectrum is typical for a sample with predominately hydrobiotite and phlogopite/biotite. The 1.40/1.42 micron band depth ratio plots just below the “no detectable amphibole, talc, and serpentine” line in Figures GDS906.spectrum.2 and 3. This reflectance spectrum of this sample does not have a detectable 2.24-micron band so there is no symbol on Fig. GDS906.spectrum.4. The spectral parameters plot in the Palabora field (Figs. GDS906.spectrum.2 and 3).

SPECTRAL_PURITY: 1b2_3_4_ # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns