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DOCUMENTATION_FORMAT: MINERAL
SAMPLE_ID: NMNH120049
MINERAL_TYPE: Inosilicate
MINERAL: Augite (Pyroxene group)
FORMULA: (Ca,Na)(Mg,Fe,Al,Ti)(Si,Al)2O6
FORMULA_HTML: (Ca,Na)(Mg,Fe,Al,Ti)(Si,Al)2O6
COLLECTION_LOCALITY: Rozier (nr.), Gorges du Tarn, Tarn, France
ORIGINAL_DONOR: National Museum of Natural History (Smithsonian)
CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
SAMPLE_DESCRIPTION:
Diopside and hedenbergite form a complete solid solution series with
physical and optical properties varying linearly with composition.
Augite is a clinopyroxene in which some Na substitutes for Ca, some
Al substitutes for both Mg (or Fe) and Si, and in which Fe and Mg
contents are higher than in diopside or hedenbergite.
"Results of petrographic examination: One 22.31g. piece, black, probably part of one crystal; some veining with lighter mineral (serpentine?) difficult to remove. Microscopic examination of hand-picked sample indicates about 1-2% contamination by low-index, iron stained mineral. Cleavage is virtually nonexistent, however, index of refraction and 2V point to augite."
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:
Augite + dolomite (m). (Norma Vergo)
Sample is augite plus a moderate amount of dolomite. Sample subsequently treated with warm HCl to remove dolomite.
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: EPMA # XRF, EPMA, ICP(Trace), WChem
| COMPOSITION KEYWORD |
Oxide ASCII |
Amount | Weight Percent, % |
Oxide html |
|---|---|---|---|---|
| COMPOSITION: | SiO2 | 48.93 | wt% | SiO2 |
| COMPOSITION: | TiO2 | 1.38 | wt% | TiO2 |
| COMPOSITION: | Al2O3 | 8.44 | wt% | Al2O3 |
| COMPOSITION: | FeO | 8.59 | wt% | FeO |
| COMPOSITION: | MnO | 0.21 | wt% | MnO |
| COMPOSITION: | MgO | 14.37 | wt% | MgO |
| COMPOSITION: | CaO | 16.87 | wt% | CaO |
| COMPOSITION: | Na2O | 1.57 | wt% | Na2O |
| COMPOSITION: | K2O | 0.02 | wt% | K2O |
| COMPOSITION: | Total | 100.38 | wt% | |
| COMPOSITION: | O=Cl,F,S | wt% | #correction for Cl, F, S | |
| COMPOSITION: | New Total | wt% |
COMPOSITION_TRACE: None
COMPOSITION_DISCUSSION:
Average of 10 samples.
"Microprobe analysis shows the sample to be homogeneous within and between grains. Sample could be classified as "ferroan augite". It has relatively high aluminum, iron and soda, and low calcium. Analysis indicates WO34, EN45, FS21 composition."
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:
"Microscopic examination of hand-picked sample indicates about 1-2% contamination by low-index, iron stained mineral. Cleavage is virtually nonexistent, however, index of refraction and 2V point to augite."
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_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