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(For further information on spectrsocopy, see:
http://speclab.cr.usgs.gov)
TITLE: Diaspore HS416 DESCRIPT
DOCUMENTATION_FORMAT: MINERAL
SAMPLE_ID: HS416
MINERAL_TYPE: Hydroxide
MINERAL: Diaspore
FORMULA: AlO(OH)
FORMULA_HTML: AlO(OH)
COLLECTION_LOCALITY: Rosebud, MO
ORIGINAL_DONOR: Hunt and Salisbury Collection
CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
SAMPLE_DESCRIPTION:
"Dimorphic with Boehmite. This sample is impure and is a mixture of bauxite minerals including gibbsite, kaolinite and a very small amount of a ferruginous material. At wavelengths longer than 1.3µm the reflectance of the sample decreases. The sample has a 1.4 µm absorption (overtone of the hydroxyl) and a 1.8 µm absorption which is believed to be a displaced 1.9µm resulting from the presence of a free H2O molecule."
Hunt, G.R., J.W. Salisbury, and C.J. Lenhoff, 1971, Visible and near-infrared spectra of minerals and rocks: III. Oxides and hydroxides. Modern Geology, v. 2, p. 195-205.
END_SAMPLE_DESCRIPTION.
XRD_ANALYSIS: Pure diaspore.
Konnert, Judith and Marta Flohr, 1992, unpublished data, USGS Reston, VA.
END_XRD_ANALYSIS.
COMPOSITIONAL_ANALYSIS_TYPE: None # XRF, EM(WDS), ICP(Trace), WChem
COMPOSITION_TRACE: None
COMPOSITION_DISCUSSION:
END_COMPOSITION_DISCUSSION.
MICROSCOPIC_EXAMINATION:
Bimodal grain size distribution:
population 1 = 268 µm at 92 vol%
population 2 = 10 µm at 8 vol%
average grain size = 257 µm
Small grains coat larger grains. Large grains are translucent and this makes it difficult to obtain optical properties. I recommend that this sample be x-rayed for proper identification. No fizz with HCl. G. Swayze.
END_MICROSCOPIC_EXAMINATION.
SPECTROSCOPIC_DISCUSSION:
END_SPECTROSCOPIC_DISCUSSION.
SPECTRAL_PURITY: 1a2_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 1388 | 0.2-3.0µm | 200 | g.s.= 257 µm |
| LIB_SPECTRA: | splib05a r 2333 | 0.2-3.0µm | 200 | g.s.= |
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