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(For further information on spectrsocopy, see:
http://speclab.cr.usgs.gov)
TITLE: Hectorite SHCa-1 AC-B DESCRIPT
DOCUMENTATION_FORMAT: MINERAL
SAMPLE_ID: SHCa-1
MINERAL_TYPE: Phyllosilicate
MINERAL: Hectorite (Montmorillonite group)
FORMULA: Na0.33(Mg,Li)3Si4O10(F,OH)2
FORMULA_HTML: Na0.33(Mg,Li)3Si4O10(F,OH)2
COLLECTION_LOCALITY: San Bernadino, California
ORIGINAL_DONOR: Grim Collection
CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
SAMPLE_DESCRIPTION:
Trioctahedral lithium montmorillonite (stored in H20).
END_SAMPLE_DESCRIPTION.
XRD_ANALYSIS:
Hectorite + quartz (m) + calcite (L) + dolomite (s)? (before acetate treatment) (Norma Vergo)
This sample was treated with acetate to dissolve carbonates. There is no fizz with HCl. Clay grains have sweeping extinction, quartz present but no evidence of calcite or dolomite. All consistent with a fairly pure sample of hectorite. G. Swayze.
END_XRD_ANALYSIS.
COMPOSITIONAL_ANALYSIS_TYPE: XRF # XRF, EM(WDS), ICP(Trace), WChem
| COMPOSITION KEYWORD |
Oxide ASCII |
Amount | Weight Percent, % |
Oxide html |
|---|---|---|---|---|
| COMPOSITION: | SiO2 | 34.7 | wt% | SiO2 |
| COMPOSITION: | TiO2 | 0.038 | wt% | TiO2 |
| COMPOSITION: | Al2O3 | 0.69 | wt% | Al2O3 |
| COMPOSITION: | Fe2O3 | 0.02 | wt% | Fe2O3 |
| COMPOSITION: | FeO | 0.25 | wt% | FeO |
| COMPOSITION: | MnO | 0.008 | wt% | MnO |
| COMPOSITION: | MgO | 15.3 | wt% | MgO |
| COMPOSITION: | CaO | 23.4 | wt% | CaO |
| COMPOSITION: | Li2O | 2.18 | wt% | Li2O |
| COMPOSITION: | Na2O | 1.26 | wt% | Na2O |
| COMPOSITION: | K2O | 0.13 | wt% | K2O |
| COMPOSITION: | P2O5 | 0.014 | wt% | P2O5 |
| COMPOSITION: | F | 2.60 | wt% | F |
| COMPOSITION: | F | 2.75 | wt% | F |
| COMPOSITION: | S | 0.01 | wt% | S |
| COMPOSITION: | LOI | 21.80 | wt% | LOI |
| COMPOSITION: | Total | 99.80 | wt% | |
| COMPOSITION: | O=Cl,F,S | wt% | #correction for Cl, F, S | |
| COMPOSITION: | New Total | wt% |
COMPOSITION_TRACE:
None
COMPOSITION_DISCUSSION:
None
END_COMPOSITION_DISCUSSION.
MICROSCOPIC_EXAMINATION:
Mode:
99 vol% hectorite
1 vol% quartz
trace opaques (metallic luster)
Bimodal Grain Size Distribution:
mode 1: 204 µm @ 80 vol%
mode 2: 25 µm @ 20 vol%
average grain size = 183 µm
This sample was treated with acetate to dissolve carbonates. There is no fizz with HCl. Clay grains have sweeping extinction, quartz present but no evidence of calcite or dolomite. All consistent with a fairly pure sample of hectorite. G. Swayze.
END_MICROSCOPIC_EXAMINATION.
SPECTROSCOPIC_DISCUSSION:
END_SPECTROSCOPIC_DISCUSSION.
SPECTRAL_PURITY: 1b2_3_4_ # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
| LIB_SPECTRA_HED: | where | Wave Range | Av_Rs_Pwr | Comment |
|---|---|---|---|---|
| LIB_SPECTRA: | splib04a r 1974 | 0.2-3.0µm | 200 | g.s.= 183 µm |
| LIB_SPECTRA: | splib04a r 1985 | 0.2-3.0µm | 200 | g.s.= 183 µm |
| LIB_SPECTRA: | splib05a r 3126 | 0.2-3.0µm | 200 | g.s.= |
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