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(For further information on spectroscopy, see:
http://speclab.cr.usgs.gov)
TITLE: Hydrogrossular NMNH120555 DESCRIPT
DOCUMENTATION_FORMAT: MINERAL
SAMPLE_ID: NMNH120555
MINERAL_TYPE: Nesosilicate
MINERAL: Hydrogrossular (Garnet group)
FORMULA: Ca3Al2(SiO4)3-x(OH)4x
FORMULA_HTML: Ca3Al2(SiO4)3-x(OH)4x
COLLECTION_LOCALITY: Rustenberg, South Africa
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.
Sample was sieved to the grain size interval less than 250µm.
IMAGE_OF_SAMPLE:
END_SAMPLE_DESCRIPTION.
XRD_ANALYSIS:
40 kV - 30 mA, 6.5-9.5 keV
File: hydrg120.out, *.mdi (smear mount on quartz plate)
References: Borg and Smith (1969), JCPDS #10-288, DHZ, v. 1a (1982),
Huebner's reference patterns
Found: Garnet; unidentified moderate to weak reflections at 6.0, 4.0, 3.58,
3.23, 3.17, 2.75, 2.59. and 1.76 Angstroms.
Sought but not found: anorthite, Fe-oxyhydroxides, ilmenite,
apophyllite, prehnite, thaumasite, gehlenite, xonotlite.
Comment: The garnet unit cell dimension ranges more or less continuously from 11.95 to 11.89 Angstroms, consistent with grossular-rich members of the grossular-hydrogrossular series. Optically the material consists of colorless, weakly anisotropic garnet and about 10% brownish weakly anisotropic garnet charged with opaque and a few bright red (hematite?)inclusions
J.S. Huebner, J. Pickrell, and T. Schaefer, 1994, written communication.
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 | 31.44 | wt% | SiO2 |
| COMPOSITION: | TiO2 | 0.04 | wt% | TiO2 |
| COMPOSITION: | Al2O3 | 21.40 | wt% | Al2O3 |
| COMPOSITION: | Cr2O3 | 0.00 | wt% | Cr2O3 |
| COMPOSITION: | V2O3 | 0.00 | wt% | V2O3 |
| COMPOSITION: | FeO | 0.46 | wt% | FeO |
| COMPOSITION: | NiO | 0.00 | wt% | NiO |
| COMPOSITION: | MnO | 0.89 | wt% | MnO |
| COMPOSITION: | MgO | 0.17 | wt% | MgO |
| COMPOSITION: | CaO | 36.14 | wt% | CaO |
| COMPOSITION: | Total | 90.54 | wt% | |
| COMPOSITION: | O=Cl,F,S | wt% | #correction for Cl, F, S | |
| COMPOSITION: | New Total | wt% |
COMPOSITION_TRACE:
COMPOSITION_DISCUSSION:
EM analysis by Gregg A. Swayze at the USGS Branch of Geophysics, Denver.
END_COMPOSITION_DISCUSSION.
MICROSCOPIC_EXAMINATION:
END_MICROSCOPIC_EXAMINATION.
SPECTROSCOPIC_DISCUSSION:
END_SPECTROSCOPIC_DISCUSSION.
SPECTRAL_PURITY: 1b2b3b4_ # 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 2229 | 0.2-3.0µm | 200 | g.s.= |
| LIB_SPECTRA: | splib05a r 3392 | 0.2-3.0µm | 200 | g.s.= |
| LIB_SPECTRA: | splib06a r 10236 | g.s.= | ||
| LIB_SPECTRA: | splib06a r 10249 | g.s.= |