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(For further information on spectrsocopy, see:
http://speclab.cr.usgs.gov)
TITLE: Hornblende HS177 DESCRIPT
DOCUMENTATION_FORMAT: MINERAL
SAMPLE_ID: HS177
MINERAL_TYPE: Inosilicate
MINERAL: Hornblende (Amphibole group)
FORMULA: Ca2(Mg,Fe+2)4Al(Si7Al)O22(OH,F)2
FORMULA_HTML: Ca2(Mg,Fe+2)4Al(Si7Al)O22(OH,F)2
COLLECTION_LOCALITY: Gore Mtn, New York
ORIGINAL_DONOR: Hunt and Salisbury Collection
CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
SAMPLE_DESCRIPTION:
Forms series from Magnesiohornblende to Ferrohornblende.
"S-1G. Amphibole, variety Hornblende. Gore Mountain, N.Y. (177B). This sample is exceptionally pure hornblende. As in samples S-1E and S-1F, note weakness of hydroxyl bands and general low reflectivity throughout, but particularly to shorter wavelengths, due to the presence of abundant ferric and ferrous ions."
Sieve interval 74 - 250µm.
Hunt, G.R., J.W. Salisbury, 1970, Visible and near-infrared spectra of minerals and rocks: I. Silicate minerals. Modern Geology, v. 1, p. 283-300.
"Results of petrographic examination: Specimen is a cluster of very dark green single crystals half a centimeter to one centimeter in length and almost as wide."
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.
END_SAMPLE_DESCRIPTION.
XRD_ANALYSIS:
40 kV - 30 mA, 7.3-9.5 keV
File: hnbld177.out, -.mdi
References: Huebner's reference patterns
Found: clinoamphibole, K-mica, K-feldspar, Na-feldspar,
clinopyroxene,unindexed reflection at 2.1 angstroms.
Comment: The clinoamphibole pattern is consistent with hornblende. All reflections are sharp, suggesting good crystallinity and compositional heterogeneity.
J.S. Huebner, J. Pickrell, T. Schaefer, written communication(USGS)
Hornblende + trace other (Norma Vergo).
"Hornblende + trace of unidentifiable mineral."
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.
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 | 41.50 | wt% | SiO2 |
| COMPOSITION: | TiO2 | 2.89 | wt% | TiO2 |
| COMPOSITION: | Al2O3 | 12.97 | wt% | Al2O3 |
| COMPOSITION: | FeO | 15.43 | wt% | FeO |
| COMPOSITION: | MnO | 0.13 | wt% | MnO |
| COMPOSITION: | MgO | 11.49 | wt% | MgO |
| COMPOSITION: | CaO | 11.34 | wt% | CaO |
| COMPOSITION: | Na2O | 1.61 | wt% | Na2O |
| COMPOSITION: | K2O | 1.71 | wt% | K2O |
| COMPOSITION: | Total | 99.08 | wt% | |
| COMPOSITION: | O=Cl,F,S | wt% | #correction for Cl, F, S | |
| COMPOSITION: | New Total | wt% |
COMPOSITION_TRACE: None
COMPOSITION_DISCUSSION:
"Microprobe analysis shows the sample to be homogeneous within and between grains. Average of 10 grains."
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.
END_COMPOSITION_DISCUSSION.
MICROSCOPIC_EXAMINATION:
Mode:
77 vol% Hornblende
15 vol% Biotite? (biaxial -, brown, low 2v)
6 vol% Other amphibole
2 vol% plagioclase (twinning)
average grain sz = 190 µm
Hornblende has amphibole cleavage, strongly brown pleochroic, OAP ll (010) = 10 degrees, biaxial (-), inclinded extinction. All these properties are consistent with hornblende. Biotite or brown mica has basal cleavage, low 2v, and biaxial (-). Other prismatic amphibole? This mineral is clear, non-pleochroic, high order color, biaxial (+), inclinded extinction. Although this sample is contaminated, a combination of Franz Seperator and heavy liquids will probably separate out the hornblende. G. Swayze.
END_MICROSCOPIC_EXAMINATION.
SPECTROSCOPIC_DISCUSSION:
END_SPECTROSCOPIC_DISCUSSION.
SPECTRAL_PURITY: 1c2_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 2208 | 0.2-3.0µm | 200 | g.s.= 190 µm |
| LIB_SPECTRA: | splib05a r 3346 | 0.2-3.0µm | 200 | g.s.= |
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