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DOCUMENTATION_FORMAT: Man_Made
SAMPLE_ID: GDS460
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 is from the attic of a home in Denver, Colorado and was collected about 2002. The home was probably built during the 1920’s. The vermiculite and fiberglass may have been added to the attic at different times.
ORIGINAL_DONOR:
CURRENT_SAMPLE_LOCATION: USGS Denver, CO
ULTIMATE_SAMPLE_LOCATION: USGS Denver, CO
SAMPLE_DESCRIPTION:
The sample has a mottled golden color with occasional dark grains and grain range in size from 1 – 4 mm. Vermiculite is mixed with fiberglass insulation (Fig. GDS460.photo.1).
Because of the limited volume of this sample (< 100 cm3) the modified Cincinnati Method was not performed. Instead, a sample container dab from the bulk sample was collected on a stub for SEM examination.
Sample has a spectral signature similar to that of expanded vermiculite ore from Enoree, South Carolina, USA.
Original spectrum published in:
IMAGE_OF_SAMPLE:
END_SAMPLE_DESCRIPTION.
XRD_ANALYSIS:
Rietveld refinement XRD analysis (limited quantities of sample and no internal standard) of hand picked trace contaminants in the sample indicates the presence of orthoclase, phlogopite, vermiculite and kaolinite (Fig. GDS460.XRD.2). Qualitative XRD analysis of the bulk sample indicates the presence of vermiculite, hydrobiotite, biotite, phlogopite, and possible amphibole (Fig. GDS460.XRD.3).
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 on flakes from the sample plot in the central Enoree fields on the Al/Ti versus Al/[Mg/(Mg+Fe)] diagram (Fig. GDS460.microprobe.1).
END_COMPOSITION_DISCUSSION.
MICROSCOPIC_EXAMINATION:
The sample was examined with SEM and Energy dispersive spectroscopy. The container lid was dabbed with an SEM stub, which was subsequently coated with carbon, and examined under high magnification. Points analyzed with EDS are shown in color on SEM micrographs that accompany the EDS spectra. Glass fiber, K-feldspar, plagioclase, gypsum, calcite, quartz, and barite were identified based on SEM and EDS analyses (Figs. GDS460.EDS.1 to 30 and GDS460.SEM. 1 to 5). Abundant glass fibers made it difficult to confirm the presence of amphibole.
END_MICROSCOPIC_EXAMINATION.
SPECTROSCOPIC_DISCUSSION:
The spectrum is typical for a sample with vermiculite. 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 Enoree/Jiangsu field (Fig. GDS460.spectrum.2) and Louisa/Enoree fields (Fig. GDS460.spectrum.3 and 4).
SPECTRAL_PURITY: 1b2_3_4_ # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns