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(For further information on spectrsocopy, see:
http://speclab.cr.usgs.gov)
TITLE: Albite GDS30 Plagioclase DESCRIPT
DOCUMENTATION_FORMAT: MINERAL
SAMPLE_ID: GDS30 and NMNH C5390
MINERAL_TYPE: Tectosilicate
MINERAL: Albite (Plagioclase, Na end member)(Feldspar group)
FORMULA: NaAlSi3O8
FORMULA_HTML: NaAlSi3O8
COLLECTION_LOCALITY: Rutherford, VA
ORIGINAL_DONOR: Jack Salisbury
CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
SAMPLE_DESCRIPTION:
Spectra from 2.5 to 25 µm for this sample are published in:
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.
"Sample is translucent and light gray to white in color. This is the classic Amelia albite. Hand specimen is large (2 cm) fragment of twinned crystal. Appears very fresh. Is translucent and light gray to white in color."
Sample measured for the library is the 74-250µm interval.
END_SAMPLE_DESCRIPTION.
XRD_ANALYSIS:
Pure albite.
END_XRD_ANALYSIS.
COMPOSITIONAL_ANALYSIS_TYPE: EM # XRF, EM(WDS), ICP(Trace), WChem
| COMPOSITION KEYWORD |
Oxide ASCII |
Amount | Weight Percent, % |
Oxide html |
|---|---|---|---|---|
| COMPOSITION: | SiO2 | 68.18 | wt% | SiO2 |
| COMPOSITION: | TiO2 | 0.01 | wt% | TiO2 |
| COMPOSITION: | Al2O3 | 20.07 | wt% | Al2O3 |
| COMPOSITION: | FeO | 0.01 | wt% | FeO |
| COMPOSITION: | MnO | 0.01 | wt% | MnO |
| COMPOSITION: | MgO | 0.02 | wt% | MgO |
| COMPOSITION: | CaO | 0.02 | wt% | CaO |
| COMPOSITION: | Na2O | 10.37 | wt% | Na2O |
| COMPOSITION: | K2O | 0.20 | wt% | K2O |
| COMPOSITION: | Total | 99.88 | wt% | |
| COMPOSITION: | O=Cl,F,S | wt% | #correction for Cl, F, S | |
| COMPOSITION: | New Total | wt% |
COMPOSITION_TRACE: None
COMPOSITION_DISCUSSION:
"Flame photometry and atomic absorption analysis of samples from the same location (not the same sample) show 98.42 mole percent albite. Microprobe analysis shows sample to be homogeneous within and between grains. Ten analyses indicate pure albite end member compostion."
Analysis from Salisbury, J. W., Walter, L. W., and Vergo, N., 1987, Mid-Infrared (2.1-25 µm) Spectra of Minerals: First Edition, U.S. Geological Survey Open File Report 87-263.
END_COMPOSITION_DISCUSSION.
MICROSCOPIC_EXAMINATION:
avg. grain size = 190µm
Clear tabular grains, mostly cleavage bound grains. 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 95 | 0.2-3.0µm | 200 | g.s.= |
| LIB_SPECTRA: | splib05a r 144 | 0.2-3.0µm | 200 | g.s.= 190 µm |
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