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Clark and others 2007 USGS Data Series 231
Spectral Library splib06a Sample Description

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

TITLE: Annite WS661 DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: WS661

MINERAL_TYPE: Phyllosilicate

MINERAL: Annite (Mica group)

FORMULA: K(Fe+2)3AlSi3O10(OH,F)2

FORMULA_HTML: KFe+23AlSi3O10(OH,F)2

COLLECTION_LOCALITY: Faraday, Ontario, Canada

ORIGINAL_DONOR: Wards Scientific

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

The sample appears uniform dark green and the visible-NIR spectrum shows strong iron bands and a spectrum typical of pure annite. The sample is darker than WS660 and the absorption features near 2.3-µm are weaker, possibly indicating a more iron rich end-member than WS660.

IMAGE_OF_SAMPLE:
Photo of sample

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

Trioctahedral mica - major - probably a mixture of compositions. No other components.

Konnert, Judith and Marta Flohr, 1992, unpublished data, USGS Reston, VA.

40 kV - 30 mA, 7.3-9.5 keV
File: annit661.out, -.mdi (smear mount on quartz plate)
References: Huebner's reference patterns
Found: trioctahedral mica, 3T or 1M polytype, un indexed weak reflections at 8.8 and 4.24 Angstroms

Comment: Non-basal reflections are surprisingly weak, even considering the smear mount. Some peak broadening or splitting, as in WS-660. Based on the position of the (060) reflection, could not distinguish between siderophyllite (60-100%) - annite solution or annite (70-90%) - phlogopite solution.

J.S. Huebner, J. Pickrell, T. Schaefer, written communication(USGS)

END_XRD_ANALYSIS.

COMPOSITIONAL_ANALYSIS_TYPE: EM(WDS) # XRF, EM(WDS), ICP(Trace), WChem
COMPOSITION
KEYWORD		 Oxide
ASCII		 Amount Weight
Percent, %		 Oxide
html
COMPOSITION: SiO2 33.489 wt% SiO2
COMPOSITION: TiO2 0.542 wt% TiO2
COMPOSITION: Al2O3 14.513 wt% Al2O3
COMPOSITION: FeO 33.840 wt% FeO
COMPOSITION: MnO 1.775 wt% MnO
COMPOSITION: MgO 0.006 wt% MgO
COMPOSITION: CaO 0.011 wt% CaO
COMPOSITION: Na2O 0.360 wt% Na2O
COMPOSITION: K2O 8.876 wt% K2O
COMPOSITION: Cl 0.196 wt% Cl
COMPOSITION: F 2.060 wt% F
COMPOSITION: Total 95.667 wt%
COMPOSITION: O=Cl,F,S wt% #correction for Cl, F, S
COMPOSITION: New Total wt%

COMPOSITION_TRACE: None

COMPOSITION_DISCUSSION:

None

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

Bimodal grain size distribution:

population 1 160µm 90 vol%
population 2 25µm 10 vol%

avg. grain size of populations = 150µm

Pure sample, large grains 60% coated with smaller grains, slight pleochroism. G. Swayze.

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1b2b3b4_ # 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 446 0.2-3.0µm 200 g.s.=150 µm
LIB_SPECTRA: splib05a r 1062 0.2-3.0µm 200 g.s.=
LIB_SPECTRA: splib06a r 2499 g.s.=
LIB_SPECTRA: splib06a r 2513 g.s.=