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DOCUMENTATION_FORMAT: MINERAL
SAMPLE_ID: VTx-1.a
MINERAL_TYPE: Phyllosilicate
MINERAL: Vermiculite
FORMULA: (Mg,Fe+2,Al)3(Al,Si)4O10(OH)2*4H2O
FORMULA_HTML: (Mg,Fe+2,Al)3(Al,Si)4O10(OH)2•4H2O
COLLECTION_LOCALITY: Llano, Texas
ORIGINAL_DONOR: Clay Mineral Repository
CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
SAMPLE_DESCRIPTION:
less than 250 microns.
IMAGE_OF_SAMPLE:
END_SAMPLE_DESCRIPTION.
XRD_ANALYSIS:
Not vermiculite - not pure (Norma Vergo).
Spectrally pure, but not chemically pure. (Norma Vergo).
There is some confusion on whether this is a pure vermiculite.
END_XRD_ANALYSIS.
COMPOSITIONAL_ANALYSIS_TYPE: XRF # XRF, EPMA, ICP(Trace), WChem
| COMPOSITION KEYWORD |
Oxide ASCII |
Amount | Weight Percent, % |
Oxide html |
|---|---|---|---|---|
| COMPOSITION: | SiO2 | 19.5 | wt% | SiO2 |
| COMPOSITION: | TiO2 | less than 0.02 | wt% | TiO2 |
| COMPOSITION: | Al2O3 | 1.53 | wt% | Al2O3 |
| COMPOSITION: | Fe2O3 | 0.56 | wt% | Fe2O3 |
| COMPOSITION: | MnO | 0.03 | wt% | MnO |
| COMPOSITION: | MgO | 27.7 | wt% | MgO |
| COMPOSITION: | CaO | 17.7 | wt% | CaO |
| COMPOSITION: | Na2O | 0.26 | wt% | Na2O |
| COMPOSITION: | K2O | 0.03 | wt% | K2O |
| COMPOSITION: | P2O5 | less than 0.05 | wt% | P2O5 |
| COMPOSITION: | LOI | 32.7 | wt% | LOI |
| COMPOSITION: | Total | wt% |
COMPOSITION_TRACE:
COMPOSITION_DISCUSSION:
END_COMPOSITION_DISCUSSION.
MICROSCOPIC_EXAMINATION:
END_MICROSCOPIC_EXAMINATION.
SPECTROSCOPIC_DISCUSSION:
Spectrum resembles that of pure Mg-Al vermiculite. Samples from Llano, Texas can contain magnesite contamination, but there is no spectral evidence for this phase in the UV-NIR spectral region. G. Swayze.
END_SPECTROSCOPIC_DISCUSSION.
SPECTRAL_PURITY: 1b2_3_4_ # VTx-1.a # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns