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DOCUMENTATION_FORMAT: MINERAL
SAMPLE_ID: HS17.1B, HS17.2B, HS17.3B, HS17.4B
MINERAL_TYPE: Tectosilicate
MINERAL: Labradorite (Plagioclase, Feldspar group)
FORMULA: (NaAlSi,CaAl2)Si2O8
FORMULA_HTML: (NaAlSi,CaAl2)Si2O8
COLLECTION_LOCALITY: Ontario
ORIGINAL_DONOR: Hunt and Salisbury Collection
CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
SAMPLE_DESCRIPTION:
"T-10 Labradorite 17B--Ontario. This plagioclase feldspar is composed of 30 to 50% albite. The spectrum of this sample is relatively flat and has a low reflectivity caused by the presence of magnetite as a microscopic disseminated impurity. We cannot account specifically for the maximum in reflectivity near 1.0µ in this spectrum. It is due to exceptionally broad, very weak absorptions on either side."
Hunt, G.R., J.W. Salisbury, and C.J. Lenhoff, 1973, Visible and near-infrared spectra of minerals and rocks: VI. Additional silicates. Modern Geology, v. 4, p. 85-106.
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
IMAGE_OF_SAMPLE:
END_SAMPLE_DESCRIPTION.
XRD_ANALYSIS:
Labradorite + 6.25, 6.34 Angstroms (small amount) (Norma Vergo, USGS)
END_XRD_ANALYSIS.
COMPOSITIONAL_ANALYSIS_TYPE: None # XRF, EPMA, ICP(Trace), WChem
COMPOSITION_TRACE: None
COMPOSITION_DISCUSSION:
None
END_COMPOSITION_DISCUSSION.
MICROSCOPIC_EXAMINATION:
Not done yet
END_MICROSCOPIC_EXAMINATION.
SPECTROSCOPIC_DISCUSSION:
END_SPECTROSCOPIC_DISCUSSION.
SPECTRAL_PURITY: 1c2_3_4_ # HS17.1B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2_3_4_ # HS17.2B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2c3b4b # HS17.3B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2_3_4_ # HS17.4B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns