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(For further information on spectrsocopy, see:
http://speclab.cr.usgs.gov)
TITLE: Andradite NMNH113829 Garnet DESCRIPT
DOCUMENTATION_FORMAT: MINERAL
SAMPLE_ID: NMNH113829
MINERAL_TYPE: Nesosilicate
MINERAL: Andradite (Garnet group)
FORMULA: Ca3(Fe+3)2(SiO4)3
FORMULA_HTML: Ca3Fe+32(SiO4)3
COLLECTION_LOCALITY: Rimpfischwange, Zermitt, Valais, Switzerland
ORIGINAL_DONOR: Smithsonian
CURRENT_SAMPLE_LOCATION: USGS Reston, VA.
ULTIMATE_SAMPLE_LOCATION: USGS Reston, VA.
SAMPLE_DESCRIPTION:
Forms series with Grossular and with Schorlomite.
The original sample description and mid-infrared spectrum was published in:
Salisbury, J. W., Walter, L. W., and Vergo, N., 1987, Mid-Infrared (2.1-25µm) Spectra of Minerals: First Edition, U.S. Geological Survey Open File Report 87-263.
END_SAMPLE_DESCRIPTION.
XRD_ANALYSIS:
Hand-picked sample is pure andradite. From:
Salisbury, J. W., Walter, L. W., and Vergo, N., 1987, Mid-Infrared (2.1-25µm) Spectra of Minerals: First Edition, U.S. Geological Survey Open File Report 87-263.
Specific XRD analysis says pure Andradite - by Norma Vergo
END_XRD_ANALYSIS.
COMPOSITIONAL_ANALYSIS_TYPE: EM(WDS) # XRF, EM(WDS), ICP(Trace), WChem
| COMPOSITION KEYWORD |
Oxide ASCII |
Amount | Weight Percent, % |
Oxide html |
|---|---|---|---|---|
| COMPOSITION: | SiO2 | 35._50 | wt% | SiO2 |
| COMPOSITION: | TiO2 | 0.07 | wt% | TiO2 |
| COMPOSITION: | Al2O3 | 0.29 | wt% | Al2O3 |
| COMPOSITION: | FeO | 28.17 | wt% | FeO |
| COMPOSITION: | MnO | 0.11 | wt% | MnO |
| COMPOSITION: | MgO | 0.14 | wt% | MgO |
| COMPOSITION: | CaO | 33.11 | wt% | CaO |
| COMPOSITION: | Na2O | 0.02 | wt% | Na2O |
| COMPOSITION: | K2O | 0.01 | wt% | K2O |
| COMPOSITION: | Total | 97.42 | wt% | |
| COMPOSITION: | O=Cl,F,S | wt% | #correction for Cl, F, S | |
| COMPOSITION: | New Total | 97.42 | wt% |
COMPOSITION_TRACE: None
COMPOSITION_DISCUSSION:
The above analysis was an average of 8 analyses and indicates nearly end-member composition. The analysis shows the sample is homogenous within and between grain boundaries.
From: Salisbury, J. W., Walter, L. W., and Vergo, N., 1987, Mid-Infrared (2.1-25µm) Spectra of Minerals: First Edition, U.S. Geological Survey Open File Report 87-263.
END_COMPOSITION_DISCUSSION.
MICROSCOPIC_EXAMINATION:
The following description is from: Salisbury, J. W., Walter, L. W., and Vergo, N., 1987, Mid-Infrared (2.1-25µm) Spectra of Minerals: First Edition, U.S. Geological Survey Open File Report 87-263.
"The sample is a cluster of subhedral crystals, green in color varying slightly with shade. Some grains are coated with a white contaminant that is soft. Dark impurities can be seen in the microscope. The white contaminant does not disappear with HCl treatment. The sample was crushed to free individual 3mm crystals and the clean bright green crystals hand picked. A few grains have a light brownish tinge on some edges. The microprobe grains appeared pure."
avg. grain size = 200µm
Clear pure grains, conchoidal fracture, isotropic under cross-polarized light. G. Swayze
END_MICROSCOPIC_EXAMINATION.
SPECTROSCOPIC_DISCUSSION:
END_SPECTROSCOPIC_DISCUSSION.
SPECTRAL_PURITY: 1a2_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 390 | 0.2-3.0µm | 200 | g.s.= |
| LIB_SPECTRA: | splib05a r 999 | 0.2-3.0µm | 200 | g.s.= |
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