DOCUMENTATION_FORMAT: MINERAL
SAMPLE_ID: CM27
MINERAL_TYPE: Phyllosilicate
MINERAL: Montmorillonite (Bentonite) (Montmorillonite group)
FORMULA: (Na,Ca)0.33(Al,Mg)2Si4O10(OH)2*nH20
FORMULA_HTML: (Na,Ca)0.33(Al,Mg)2Si4O10(OH)2•nH20
COLLECTION_LOCALITY: Belle Fourche, South Dakota
ORIGINAL_DONOR: Clay Mineral Standard, Wards Natural Science Inc
CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
SAMPLE_DESCRIPTION:
A spectrum for this sample was published by:
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.
who noted that it was spectrally pure.
END_SAMPLE_DESCRIPTION.
XRD_ANALYSIS:
Analysis by Norma Vergo indicates the sample is bentonite + quartz + feldspar + bassanite; the <2µm cut is pure smectite.
END_XRD_ANALYSIS.
COMPOSITIONAL_ANALYSIS_TYPE: XRF # XRF, EM(WDS), ICP(Trace), WChem
| COMPOSITION: | SiO2 | 57.6 | wt% | SiO2 |
| COMPOSITION: | TiO2 | 0.12 | wt% | TiO2 |
| COMPOSITION: | Al2O3 | 20.9 | wt% | Al2O3 |
| COMPOSITION: | Fe2O3 | 3.54 | wt% | Fe2O3 |
| COMPOSITION: | FeO | 0.09 | wt% | FeO |
| COMPOSITION: | MnO | <0.02 | wt% | MnO |
| COMPOSITION: | MgO | 2.66 | wt% | MgO |
| COMPOSITION: | CaO | 1.04 | wt% | CaO |
| COMPOSITION: | Na2O | 1.81 | wt% | Na2O |
| COMPOSITION: | K2O | 0.35 | wt% | K2O |
| COMPOSITION: | P2O5 | <0.05 | wt% | P2O5 |
| COMPOSITION: | H2O+ | 5.94 | wt% | H2O+ |
| COMPOSITION: | H2O- | 5.46 | wt% | H2O- |
| COMPOSITION: | H2O | 11.4 | wt% | H2O |
| COMPOSITION: | LOI | 11.3 | wt% | LOI |
| COMPOSITION: | Total | 99.39 | wt% | |
| COMPOSITION: | O=Cl,F,S | wt% | #correction for Cl, F, S | |
| COMPOSITION: | New Total | wt% |
COMPOSITION_TRACE:
COMPOSITION_DISCUSSION:
XRF Analysis by Branch of Analytical Chemistry, USGS, Denver. Total above includes LOI value rather than H2O values, and does not include value for FeO as it was determined at same time as H2O. Trace analysis was performed and will be added later.
END_COMPOSITION_DISCUSSION.
MICROSCOPIC_EXAMINATION:
Trace amounts of limonite, no visible feldspar or quartz, slight HCl fizz.
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 3166 0.2-3.0µm 200 g.s.=
LIB_SPECTRA: splib05a r ____ 0.2-3.0µm 200 g.s.=
LIB_SPECTRA: splib06a r ____ 1.5-25µm 250 g.s.=