TITLE: Maghemite GDS81 Sy DESCRIPT
MINERAL: Maghemite (Synthetic)(Hematite group)
CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
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.
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 suggesta 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??
COMPOSITIONAL_ANALYSIS_TYPE: None # XRF, EM(WDS), ICP(Trace), WChem
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 ____ 0.2-3.0µm 200 g.s.=
LIB_SPECTRA: splib06a r ____ 1.5-25µm 250 g.s.=