DOCUMENTATION_FORMAT: MINERAL
SAMPLE_ID: HS66.1B, HS66.2B, HS66.3B, HS66.4B, HS66.6
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. 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
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:
Albite + trace mica. (Norma Vergo)
END_XRD_ANALYSIS.
COMPOSITIONAL_ANALYSIS_TYPE: None # XRF, EPMA, 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: 1c2_3_4_ # HS66.1B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2_3_4_ # HS66.2B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2b3b4b # HS66.3B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2_3_4_ # HS66.4B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2_3_4_ # HS66.6 # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns