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(For further information on spectroscopy, see:
http://speclab.cr.usgs.gov)
TITLE: Albite HS66 Plagioclase DESCRIPT
DOCUMENTATION_FORMAT: MINERAL
SAMPLE_ID: HS66
MINERAL_TYPE: Tectosilicate
MINERAL: Albite (Plagioclase, Na end member, Feldspar group)
FORMULA: NaAlSi3O8
FORMULA_HTML: NaAlSi3O8
COLLECTION_LOCALITY: Amelia, Virginia
ORIGINAL_DONOR: Hunt and Salisbury Collection
CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
SAMPLE_DESCRIPTION:
"This sample of albite is quite pure, and consequently has a high reflectivity throughout this wavelength range (.4-2.5 µm). The only two bands displayed (near 1.4 and 1.9 µm) are due to water in fluid inclusions."
Hunt, G.R., J.W. Salisbury, 1970, Visible and near-infrared spectra of minerals and rocks: I. Silicate minerals. Modern Geology, vol. 1, pp 283-300.
White color, 74-250µm sieve interval. This is the sodium end member of the albite-anorthite series.
Also apparent in the spectrum is a weak 2.2-µm absorption, apparently due to some alteration that is not detectable under microscopic examination. Roger N. Clark
IMAGE_OF_SAMPLE:
END_SAMPLE_DESCRIPTION.
XRD_ANALYSIS:
Albite + trace mica. (Norma Vergo)
END_XRD_ANALYSIS.
COMPOSITIONAL_ANALYSIS_TYPE: None # XRF, EM(WDS), ICP(Trace), WChem
COMPOSITION_TRACE: None
COMPOSITION_DISCUSSION:
No compositional analyses available
END_COMPOSITION_DISCUSSION.
MICROSCOPIC_EXAMINATION:
Bimodal grain size distribution:
population 1 = 190µm 99 vol%
population 2 = 8µm 1 vol%
avg. grain size of populations = 189µm
Pure feldspar. Larger grains cleavage and fracture bounded with 20% of their surfaces covered by smaller grains. No mica visible in either grains size fraction. G. Swayze
END_MICROSCOPIC_EXAMINATION.
SPECTROSCOPIC_DISCUSSION:
END_SPECTROSCOPIC_DISCUSSION.
SPECTRAL_PURITY: 1c2b3b4b # 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 117 | 0.2-3.0µm | 200 | g.s.= 189 µm |
| LIB_SPECTRA: | splib05a r 168 | 0.2-3.0µm | 200 | g.s.= |
| LIB_SPECTRA: | splib06a r 457 | g.s.= | ||
| LIB_SPECTRA: | splib06a r 469 | g.s.= |