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(For further information on spectrsocopy, see:
http://speclab.cr.usgs.gov)
TITLE: Maghemite GDS81 Syn (M-3) DESCRIPT
DOCUMENTATION_FORMAT: MINERAL
SAMPLE_ID: GDS81
MINERAL_TYPE: Oxide
MINERAL: Maghemite (Synthetic)(Hematite group)
FORMULA: gamma-Fe2O3
FORMULA_HTML: gamma-Fe2O3
COLLECTION_LOCALITY: Synthetic
ORIGINAL_DONOR: Not available
CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
SAMPLE_DESCRIPTION:
This sample is one of a series of sample synthesized for the following paper:
Sherman, D.M., R.G. Burns, and V.M. Burns, 1982, Spectral characteristics of the iron oxides with application to the Martian bright region mineralogy. Journal of Geophysical Research, v. 87, n. B12, pp. 10169- 10180.
Maghemite is formed either by the oxidation of magnetite or by the thermal dehydration of lepidocrosite.
The spectrum of our sample, M-3 most closely matches the spectrum of sample M-4A in the above paper. M-4 was produced by thermal oxidation of magnetite. The Mossbauer spectrum of that sample showed no evidence of a magnetite component. The X-ray patterns confirmed the identity of the sample and the TEM data indicated that the sample was well crystallized.
END_SAMPLE_DESCRIPTION.
XRD_ANALYSIS:
40 kV - 30 mA, 7.3-9.5 keV
File: maghmt81.out, -.mdi
References: Maghemite C (JCPDS 39-1346), Maghemite Q (JCPDS 12-1402) and Magnetite
(Huebner's reference patterns).
Found: maghemite C, maghemite Q and/or magnetite; quartz
Comment: 5 very broad, very weak reflections correspond to a very poorly crystallized
oxide phase, but the X-ray powder pattern does not reveal which one. The brown
color suggest that magnetite, if present, is minor. Five reflections of quartz;
the (100) and (101) are very sharp, suggesting well-crystallized quartz, rather
than a precursor. What is quartz doing in a synthetic iron oxide preparation??
END_XRD_ANALYSIS.
COMPOSITIONAL_ANALYSIS_TYPE: None # XRF, EM(WDS), ICP(Trace), WChem
COMPOSITION_TRACE:
COMPOSITION_DISCUSSION:
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 2842 | 0.2-3.0µm | 200 | g.s.= |
| LIB_SPECTRA: | splib05a r 4232 | 0.2-3.0µm | 200 | g.s.= |
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