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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: Microcline HS151 Feldspar DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: HS151

MINERAL_TYPE: Tectosilicate

MINERAL: Microcline (Feldspar group)

FORMULA: KAlSi3O8

FORMULA_HTML: KAlSi3O8

COLLECTION_LOCALITY: Custer County, Colorado

ORIGINAL_DONOR: Hunt and Salisbury Collection

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

Dimorphous with Orthoclase.

"The microcline spectra shows fairly weak H2O features near 1.4 and 1.9µ, and a very weak feature near 2.2µ due to the OH stretch-AlOH bend combination. It also displays a quite sharp drop off at approximately 0.55µ which is typical of the ferric oxides. Sample is pinkish in color, which is not due to an alteration coating of ferric oxide. Deer et al. (1963) point out that Fe3+ may substitute for Al in limited amount in normal alkali feldspars, but excess Fe3+ will exsolved either as discrete particles of iron-bearing mineral, or as an iron staining on grain boundaries and cleavage planes. The latter appears to be the case for this microcline, which explains the ferric oxide type of visible spectrum. There is, however, insufficient ferric oxide present to yield a discernible near-infrared feature."

Sieve interval 74 - 250µm.

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.

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

Max. microcline + albite(l) + mica(s)

END_XRD_ANALYSIS.

COMPOSITIONAL_ANALYSIS_TYPE: None # XRF, EM(WDS), 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_ # 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 3023 0.2-3.0µm 200 g.s.=
LIB_SPECTRA: splib05a r 4390 0.2-3.0µm 200 g.s.=


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