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USGS Spectral Library Version 7 Sample Description

Kokaly, R.F., Clark, R.N., Swayze, G.A., Livo, K.E., Hoefen, T.M., Pearson, N.C., Wise, R.A., Benzel, W.M., Lowers, H.A., Driscoll, R.L., and Klein, A.J., 2017, USGS Spectral Library Version 7: U.S. Geological Survey Data Series 1035, 61 p., https://doi.org/10.3133/ds1035
For more information on the library, see: local link web link

TITLE: Microcline HS103 Feldspar DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: HS103.1B, HS103.2B, HS103.3B, HS103.4B, HS103.6

MINERAL_TYPE: Tectosilicate

MINERAL: Microcline (Feldspar group)

FORMULA: KAlSi3O8

FORMULA_HTML: KAlSi3O8

COLLECTION_LOCALITY: Crystal Peak, 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.

"This spectrum (103B) displays as its major feature a broad band near 1.3µ similar to the ferrous ion band in the two anorthite's above. This sample is quite pure in hand specimen, but Deer and others (1963) note that alkali feldspars are a series varying from pure KAlSi3O8 (microcline) to pure NaAlSi3O8 (albite) but they normally also contain a small amount of CaAl2-Si2O8 (anorthite). It appears that the anorthite fraction of this microcline contains substituted ferrous iron as in the anorthite's above, which also accounts for the bands in the visible at 0.38 and 0.42µ. Weak bands at 1.9 and 2.5µ are due to included water, while the 2.2µ band is due to the combination involving the AlOH bend."

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
.6 = cut slab

IMAGE_OF_SAMPLE:
Photo of sample

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

Max. microcline + albite(L) + quartz(m)

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:

A spectral feature near 2.2 microns suggests the presence of trace quantities of a kaolin group mineral. G. Swayze.

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1c2_3_4_ # HS103.1B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2_3_4_ # HS103.2B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2c3c4_ # HS103.3B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2_3_4_ # HS103.4B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2_3_4_ # HS103.6 # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns