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DOCUMENTATION_FORMAT: MINERAL
SAMPLE_ID: NMNHC2368
MINERAL_TYPE: Inosilicate
MINERAL: Hypersthene (Fe-rich enstatite, Pyroxene group)
FORMULA: (Mg,Fe+2)2Si2O6
FORMULA_HTML: (Mg,Fe+2)Si2O6
COLLECTION_LOCALITY: Western Greenland
ORIGINAL_DONOR: National Museum of Natural History
CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
SAMPLE_DESCRIPTION:
Enstatite-orthoferrosilite series member.
"Results of petrographic examination: One piece and one small fragment weighing 21.59 g. Part of single crystal; black. Very small amount of surface contamination which may be removed by scratching. Also some quartz inclusions which may be possible to break free. Under the microscope it is green-brown pleochroic with a relatively high index of refraction. It appears mildly altered with some (2%) iron-stained opaque material present."
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.
IMAGE_OF_SAMPLE:
END_SAMPLE_DESCRIPTION.
XRD_ANALYSIS:
This sample contains hypersthene plus a small amount of talc and some other minerals (small amount). No clinopyroxene exsolution seen. (Norma Vergo)
"This sample is predominantly hypersthene with a small amount of talc and a small amount of other mineral(s). However, the amount of talc appears insufficient to affect the infrared spectrum, because even the strong hydroxyl bands of talc between 3600 and 4600 cm-1, which are extremely prominent in the spectrum of the 0-74 µ size range of talc, are not obvious in the spectrum of the 0-74 µm size range of hypersthene."
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_XRD_ANALYSIS.
COMPOSITIONAL_ANALYSIS_TYPE: EM # XRF, EPMA, ICP(Trace), WChem
| COMPOSITION KEYWORD |
Oxide ASCII |
Amount | Weight Percent, % |
Oxide html |
|---|---|---|---|---|
| COMPOSITION: | SiO2 | 51.32 | wt% | SiO2 |
| COMPOSITION: | TiO2 | 0.29 | wt% | TiO2 |
| COMPOSITION: | Al2O3 | 4.89 | wt% | Al2O3 |
| COMPOSITION: | FeO | 17.07 | wt% | FeO |
| COMPOSITION: | MnO | 0.35 | wt% | MnO |
| COMPOSITION: | MgO | 26.09 | wt% | MgO |
| COMPOSITION: | CaO | 1.27 | wt% | CaO |
| COMPOSITION: | Na2O | 0.05 | wt% | Na2O |
| COMPOSITION: | K2O | 0.02 | wt% | K2O |
| COMPOSITION: | Total | 101.33 | wt% | |
| COMPOSITION: | O=Cl,F,S | wt% | #correction for Cl, F, S | |
| COMPOSITION: | New Total | wt% |
COMPOSITION_TRACE:
None
COMPOSITION_DISCUSSION:
"Microprobe analysis indicates exsolution of a small amount of clinopyroxene as shown by presence of Ca and concomitment loss of magnesium and iron for 2 out of 20 analyses."
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:
Not done yet
END_MICROSCOPIC_EXAMINATION.
SPECTROSCOPIC_DISCUSSION:
END_SPECTROSCOPIC_DISCUSSION.
SPECTRAL_PURITY: 1b2b3b4b # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns