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Clark et. al. 2003 USGS Open File Report 03-395
Spectral Library splib05a Sample Description

(For further information on spectrsocopy, see: http://speclab.cr.usgs.gov)

TITLE: Albite HS324 Plagioclase DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: HS324

MINERAL_TYPE: Tectosilicate

MINERAL: Albite (Plagioclase, Na end member)(Feldspar group)

FORMULA: NaAlSi3O8

FORMULA_HTML: NaAlSi3O8

COLLECTION_LOCALITY: South Dakota

ORIGINAL_DONOR: Hunt and Salisbury Collection

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

"This is the sodium end member of the albite-anorthite series and is composed of 90 to 100% albite. Its spectrum shows weak features near 0.65 µ (very broad) and near 1.0 µ, suggesting the presence of small amounts of both Fe+3 and Fe+2. The Fe+3 substitutes for aluminum, and the Fe+2 substitutes for the calcium, the latter in whatever anorthite is present. Hydroxyl and water bands are seen near 1.4 and 1.9 µ, and the AlOH bend OH combination feature near 2.2 µ is evident. The strength of this last band suggests incipient alteration of the sample, which is not apparent in hand specimen."

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, vol. 4, pp 85-106.

White color, 74-250µm sieve interval.

Note: the spectrum of this sample shows a significant 2.2-µm band apparently due to alteration although (see microscopic examination below) it can not be seen by visual examination. Roger N. Clark

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

Albite + 3.18(s) anorthite?? (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:

avg. grain size = 265µm

Pure sample no visible alteration or contamination, clear cleavage bounded crystals. G. Swayze

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1c2_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 106 0.2-3.0µm 200 g.s.= 265 µm
LIB_SPECTRA: splib05a r 156 0.2-3.0µm 200 g.s.=


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