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(For further information on spectrsocopy, see:
http://speclab.cr.usgs.gov)
TITLE: Spessartine NMNH14143 Garnet DESCRIPT
DOCUMENTATION_FORMAT: MINERAL
SAMPLE_ID: NMNH114143
MINERAL_TYPE: Nesosilicate
MINERAL: Spessartine (Garnet group)
FORMULA: Mn3Al2(SiO4)3
FORMULA_HTML: Mn3Al2(SiO4)3
COLLECTION_LOCALITY: Rutherford #2 Mine, Amelia, Amelia County, Virginia
ORIGINAL_DONOR: National Museum of Natural History
CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
SAMPLE_DESCRIPTION:
Forms series with Almandine.
"Results of petrographic examination: A group of 3mm and smaller diameter reddish crystals. Seem to be a few clear crystals adhering to the grains that were picked off; otherwise appears pure. Under petrographic microscope, sample appears pure."
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:
Pure spessartine.
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.
Pure spessartine (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 | 35.02 | wt% | SiO2 |
| COMPOSITION: | TiO2 | 0.07 | wt% | TiO2 |
| COMPOSITION: | Al2O3 | 20.74 | wt% | Al2O3 |
| COMPOSITION: | FeO | 10.40 | wt% | FeO |
| COMPOSITION: | MnO | 30.82 | wt% | MnO |
| COMPOSITION: | MgO | 0.04 | wt% | MgO |
| COMPOSITION: | CaO | 1.61 | wt% | CaO |
| COMPOSITION: | Na2O | 0.09 | wt% | Na2O |
| COMPOSITION: | K2O | 0.03 | wt% | K2O |
| COMPOSITION: | Total | 98.81 | wt% |
COMPOSITION_TRACE:
COMPOSITION_DISCUSSION:
Microprobe analysis found one heterogeous area where all oxides, including silica, summed to only 27 wt% (this is probably a flaw in carbon coating). Otherwise, FeO varies from 7.5 to 12%, with inverse variation in MnO. Average of 10 analyses (other than anomalous point). Analyst: Lou Walter (done on Smithsonian microprobe using WDS?)
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:
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 4499 | 0.2-3.0µm | 200 | g.s.= |
| LIB_SPECTRA: | splib05a r 6285 | 0.2-3.0µm | 200 | g.s.= |
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