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
END_SAMPLE_DESCRIPTION.
XRD_ANALYSIS:
Albite + trace mica. (Norma Vergo)
END_XRD_ANALYSIS.
COMPOSITIONAL_ANALYSIS_TYPE: None # XRF, EM(WDS), ICP(Trace), WChem
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%
av gr sz of populations = 189µm
Pure feldspar. Larger grains cleavge 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: 1_2_3_4_
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 ____ 0.2-3.0µm 200 g.s.=
LIB_SPECTRA: splib06a r ____ 1.5-25µm 250 g.s.=