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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: Paragonite GDS109 DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: GDS109

MINERAL_TYPE: Phyllosilicate

MINERAL: Paragonite (Mica group)

FORMULA: NaAl2(Si3Al)O10(OH)2

FORMULA_HTML: NaAl2(Si3Al)O10(OH)2

COLLECTION_LOCALITY: Ilas de Margarita, Venezuela

ORIGINAL_DONOR: Jim Crowley, USGS Reston

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

see:

Robie, R.A., and B.S. Hemingway, 1984, Heat capacities and entropies of phlogopite and paragonite between 5 and 900 K and estimates of the enthalpies and Gibbs free energies of formation. American Mineralogist, v.69, pp. 858-868.

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

40 kV - 30 mA, 6.5-9.5 keV (smear mount of GDS109 = parag.out; smear mount of GDS109 ground with glass = parag2.out)
References: Bailey (1988, p. 201); calculated 2M1 paragonite pattern of Borg and Smith (1969); Huebner's reference patterns
Found: dioctahedral mica
Sought but not found: quartz, muscovite, chlorite

Comments: Many expected reflections were not resolved, even following grinding with glass; non-basal reflections are broad. The position of the (004) reflection indicates the presence of a small cation such as sodium. The polytype could not be determined. Even allowing for preferred basal orientation, GDS109 is poorly crystallized. It is not of the same quality as the "muscovites" and probably should not be compared with them to attempt to ascertain K/Na from spectra. However, poorly crystallized material such as GDS109 may be more representative of micas in sedimentary environments than is the suite of "muscovites".

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

"Unit cell parameters are a = 0.5130±0.0010 nm, b = 0.8905±0.0017 nm, c = 1.9342±:0.0039 nm, and beta = 94.50.2° and the structure type is 2M1 (M.R. Ross, written communication, August 1982). These parameters are in good agreement with those reported by Chatterjee (1974) and Holland (1979) for synthetic 2M1 paragonite." Robie, R.A., and B.S. Hemingway, 1984, Heat capacities and entropies of phlogopite and paragonite between 5 and 900 K and estimates of the enthalpies and Gibbs free energies of formation. American Mineralogist, v.69, pp. 858-868.

END_XRD_ANALYSIS.

COMPOSITIONAL_ANALYSIS_TYPE: see discussion # XRF, EM(WDS), ICP(Trace), WChem

COMPOSITION
KEYWORD
Oxide
ASCII
Amount Weight
Percent, %
Oxide
html
COMPOSITION: SiO2 46.70 wt% SiO2
COMPOSITION: TiO2 0.46 wt% TiO2
COMPOSITION: Al2O3 40.50 wt% Al2O3
COMPOSITION: FeO 0.32 wt% FeO
COMPOSITION: CaO 0.40 wt% CaO
COMPOSITION: Na2O 6.90 wt% Na2O
COMPOSITION: K2O 0.73 wt% K2O
COMPOSITION: H2O+ 5.20 wt% H2O+
COMPOSITION: Total 101.21 wt%

COMPOSITION_TRACE:

COMPOSITION_DISCUSSION:

Composition information from:

Robie, R.A., and B.S. Hemingway, 1984, Heat capacities and entropies of phlogopite and paragonite between 5 and 900 K and estimates of the enthalpies and Gibbs free energies of formation. American Mineralogist, v.69, pp. 858-868. (J. Marinenko, analyst. Rapid-rock method.)

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 3820 0.2-3.0µm 200 g.s.=
LIB_SPECTRA: splib05a r 5340 0.2-3.0µm 200 g.s.=


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