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DOCUMENTATION_FORMAT: Man_Made
SAMPLE_ID: GDS847
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 was collected from the Virginia Vermiculite expansion facility in Louisa, Virginia in 2008 (courtesy of Chris Findlay, MSHA and Virginia Vermiculite, LLC).
ORIGINAL_DONOR:
CURRENT_SAMPLE_LOCATION: USGS Denver, CO
ULTIMATE_SAMPLE_LOCATION: USGS Denver, CO
SAMPLE_DESCRIPTION:
The sample has a mottled golden color with numerous dark grains and grain sizes range from 1 - 7 mm (Fig. GDS847.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 Louisa, Virginia, USA.
Original spectrum published in:
IMAGE_OF_SAMPLE:
END_SAMPLE_DESCRIPTION.
XRD_ANALYSIS:
Qualitative XRD analysis of the Cincinnati Method sink fraction indicates the presence of amphibole, talc, mica, chlorite, and vermiculite (Fig. GDS847.XRD.2).
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 center right Enoree/Louisa field and rightmost Louisa field on the Al/Ti versus Al/[Mg/(Mg+Fe)] diagram (Fig. GDS847.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. Points analyzed with EDS are shown in color on SEM micrographs that accompany the EDS spectra. EDS and SEM analyses detected amphibole, likely tremolite or actinolite (Figs. GDS847.EDS.5 and 6, and Fig. GDS847.SEM.4). This amphibole particle is not particularly elongate relative to amphiboles detected in Enoree and Libby samples. Talc or anthophyllite particles were also detected (e.g., Figs. GDS847.EDS.3 and 4, and GDS847.SEM.5; GDS847.EDS.10 to 12, and GDS847.SEM.6).
END_MICROSCOPIC_EXAMINATION.
SPECTROSCOPIC_DISCUSSION:
The spectrum is typical for a sample with vermiculite ore. The 1.40/1.42 micron band depth ratio indicates the presence of amphibole, talc, or serpentine probably at the few weight percent level. The shape of the grains of these contaminants cannot be discerned by spectroscopy. The spectral parameters plot in the Louisa field (Fig. GDS847.spectrum.2) and Louisa/Enoree field (Figs. GDS847.spectrum.3 and 4).
SPECTRAL_PURITY: 1b2_3_4_ # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns