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(For further information on spectrsocopy, see:
http://speclab.cr.usgs.gov)
TITLE: Uvarovite NMNH106661 Garnet DESCRIPT
DOCUMENTATION_FORMAT: MINERAL
SAMPLE_ID: NMNH106661
MINERAL_TYPE: Nesosilicate
MINERAL: Uvarovite (Garnet group)
FORMULA: Ca3Cr(+3)2(SiO4)3
FORMULA_HTML: Ca3Cr+32(SiO4)3
COLLECTION_LOCALITY: Unknown
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 Grossular.
The garnet group includes a series of isostructural subspecies with space group Ia3d; the crystallize in the hexoctahedral class of the isometric system and are similar in crystal habit. Garnet compositions can be expressed by the general structural formula A3B2(SiO4) where the A site houses Ca, Mg, Fe+2 or Mn+2 and the B site incorporates Al, Fe+3, and Cr+3.
END_SAMPLE_DESCRIPTION.
XRD_ANALYSIS:
40 kV - 30 mA, 6.5-9.5 keV
File: uvarv106.out, *.mdi (smear mount on quartz plate)
References: JCPDS #11-696, Huebner's reference patterns
Found: garnet, talc, minor additional phase
Comment: Talc based on three strong basal reflections. There were three unindexed
reflections at 2.940, 2.510, and 1.495 angstroms. The garnet has a=11.90 angstroms,
between that of uvarovite (12.00 angstroms) or andradite (angstroms) and grossular
(11.85 angstroms) or other garnet components with smaller cell dimensions. Based on
the intense green color, this garnet contains significant uvarovite component, but the
identity and proportions of other components is not known.
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 | 35.9700 | wt% | SiO2 |
| COMPOSITION: | TiO2 | 0.0744 | wt% | TiO2 |
| COMPOSITION: | Al2O3 | 5.7720 | wt% | Al2O3 |
| COMPOSITION: | Cr2O3 | 19.9300 | wt% | Cr2O3 |
| COMPOSITION: | V2O3 | 0.2657 | wt% | V2O3 |
| COMPOSITION: | FeO | 1.0750 | wt% | FeO |
| COMPOSITION: | NiO | 0.0099 | wt% | NiO |
| COMPOSITION: | MnO | 0.7153 | wt% | MnO |
| COMPOSITION: | MgO | 0.4420 | wt% | MgO |
| COMPOSITION: | CaO | 32.5200 | wt% | CaO |
| COMPOSITION: | Total | 96.7743 | wt% |
COMPOSITION_TRACE:
COMPOSITION_DISCUSSION:
Microprobe by G. Swayze, average of several points
END_COMPOSITION_DISCUSSION.
MICROSCOPIC_EXAMINATION:
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 5096 | 0.2-3.0µm | 200 | g.s.= |
| LIB_SPECTRA: | splib05a r 6957 | 0.2-3.0µm | 200 | g.s.= |
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