DOCUMENTATION_FORMAT: MINERAL
SAMPLE_ID: HS295.1B, HS295, HS295.3B, HS295.4B, HS295.6
MINERAL_TYPE: Sulfate
MINERAL: Alunite (Alunite group)
FORMULA: KAl3(SO4)2(OH)6
FORMULA_HTML: KAl3(SO4)2(OH)6
COLLECTION_LOCALITY: Utah
ORIGINAL_DONOR: Hunt and Salisbury Collection
CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
SAMPLE_DESCRIPTION:
Original spectrum published in:
Hunt, G.R., J.W. Salisbury, and C.J. Lenhoff, 1971, Visible and near-infrared spectra of minerals and rocks: IV. Sulphide's and sulphate's. Modern Geology, vol. 3, pp 1-14.
With the following comment: "Alunite is white when pure. This particular sample is pink, presumably because of a small amount of iron which causes the fall-off in reflectivity toward the blue. No iron bands are seen in the near-infrared."
A spectrum for this sample is also published in:
Clark, R.N., T.V.V. King, M. Klejwa, G. Swayze, and N. Vergo, 1990, High spectral resolution reflectance spectroscopy of minerals: J. Geophys Res. 12653-12680.
Grain size fractions are indicated by the extension after the sample number:
.1B = <5 µm
.2B = <74 µm
.3B = 74-250 µm
.4B = 250-1200 µm
.6 = cut slab
END_SAMPLE_DESCRIPTION.
XRD_ANALYSIS:
Analysis by Norma Vergo indicates pure Alunite
END_XRD_ANALYSIS.
COMPOSITIONAL_ANALYSIS_TYPE: XRF # XRF, EPMA, ICP(Trace), WChem
COMPOSITION KEYWORD |
Oxide ASCII |
Amount | Weight Percent, % |
Oxide html |
---|---|---|---|---|
COMPOSITION: | SiO2 | 0.17 | wt% | SiO2 |
COMPOSITION: | TiO2 | 0.02 | wt% | TiO2 |
COMPOSITION: | Al2O3 | 35.6 | wt% | Al2O3 |
COMPOSITION: | Fe2O3 | 0.14 | wt% | Fe2O3 |
COMPOSITION: | MnO | 0.02 | wt% | MnO |
COMPOSITION: | MgO | less than 0.1 | wt% | MgO |
COMPOSITION: | CaO | less than 0.02 | wt% | CaO |
COMPOSITION: | Na2O | 0.34 | wt% | Na2O |
COMPOSITION: | K2O | 10.2 | wt% | K2O |
COMPOSITION: | P2O5 | 0.75 | wt% | P2O5 |
COMPOSITION: | LOI | 44.2 | wt% | LOI |
COMPOSITION: | Total | 91.56 | wt% | |
COMPOSITION: | O=Cl,F,S | wt% | ||
COMPOSITION: | New Total | wt% |
COMPOSITION_TRACE: None
COMPOSITION_DISCUSSION:
XRF analysis by Foggert, Bartel, and Stewart USGS Branch of Analytic Chemistry, Denver from:
Salisbury, J. W., Walter, L. W., and Vergo, N., 1987, Mid-Infrared (2.1-25µm) Spectra of Minerals: First Edition, U.S. Geological Survey Open File Report 87-263.
Sulfur was not included in analysis and probably accounts for the missing 8%.
END_COMPOSITION_DISCUSSION.
MICROSCOPIC_EXAMINATION:
Salisbury, J. W., Walter, L. W., and Vergo, N., 1987, Mid-Infrared (2.1-25µm) Spectra of Minerals: First Edition, U.S. Geological Survey Open File Report 87-263.
This reference notes that the sample is slightly pink in color, appears pure.
avg. grain size = 300µm
Grains have straight extinction, length fast, uniaxial (+). G. Swayze
END_MICROSCOPIC_EXAMINATION.
SPECTROSCOPIC_DISCUSSION:
END_SPECTROSCOPIC_DISCUSSION.
SPECTRAL_PURITY: 1a2_3_4_ # Alunite HS295.1B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1a2_3_4_ # Alunite HS295 # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1a2a3a4a # Alunite HS295.3B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1a2_3_4_ # Alunite HS295.4B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1b2_3_4_ # Alunite HS295.6 # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns