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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: Carnallite HS430 DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: HS430

MINERAL_TYPE: Halide

MINERAL: Carnallite

FORMULA: KMgCl3*6H2O

FORMULA_HTML: KMgCl3•6H2O

COLLECTION_LOCALITY: Carlsbad, New Mexico

ORIGINAL_DONOR: Hunt and Salisbury Collection

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

This sample was originally described by Hunt and Salisbury as:

"H-5. Sylvite. Carlsbad, N.M. (430B). Sylvite, KC1, has the same origin, mode of occurrence and associations as halite, but is much rarer. Like halite, it is colorless when pure, but is more often some shade of red due to ferric oxide inclusions. It may also be yellow or blue, and it has been suggested that the blue coloration is due to F-centers in inclusions of rock salt. This sample is reddish orange, and the absorption less than of 0.55 µ is due to ferric oxide inclusions. The well-defined bands in the near-infrared at 1.0, 1.23, 1.46, 1.77, 1.99, and 2.27 µ are clearly due to water of hydration. Except for a small shift to longer wavelengths these bands are essentially identical with those found in gypsum (see spectra SS-11A, B, C, D, in Part IV). The sylvite obviously contains some hydrated impurity, although it does not appear to be gypsum in this case. Most probably it is magnesium chloride hydrate, but almost any hydrate produces a set of bands similar to those displayed here."

Hunt, G.R., J.W. Salisbury, and C.J. Lenhoff, 1972, Visible and near-infrared spectra of minerals and rocks: V. Halides, phosphates, arsenates, vanadates and borates. Modern Geology, v. 3, p. 121-132.

XRD has shown this sample to be primarily Carnallite. The visible and near infrared spectral features are from Carnallite.

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

45 kV - 35 mA, 6.5-9.5 keV
Reference: JCPDS #28-869
Found: Carnallite plus an unidentified reflection at 3.16-3.16 angstroms.

Comments: All strong reflections on the JCPDS card were found. The carnallite reflections are sharp, indicating good crystallinity. The unidentified reflection is broad and may be a doublet.

J.S. Huebner, J. Pickrell, and T. Schaefer, 1994, written communication.

END_XRD_ANALYSIS.

COMPOSITIONAL_ANALYSIS_TYPE: None # XRF, EM(WDS), ICP(Trace), WChem

COMPOSITION_TRACE: None

COMPOSITION_DISCUSSION:

None

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1a2_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 840 0.2-3.0µm 200 g.s.=
LIB_SPECTRA: splib05a r 1545 0.2-3.0µm 200 g.s.=


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