DOCUMENTATION_FORMAT: MINERAL
SAMPLE_ID: WS660
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.
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Konnert, Judith and Marta Flohr, 1992, unpublished data, USGS Reston, VA.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, unindexed weak
reflections at 8.8 and 4.24 angstroms
Comment: Non-basal reflections are surprisingly weak, even
copnsidering the smear mount. Some peak broadening or splitting, as
in WS-660. Based on the position of the (060) reflection, caould
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: | 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%
av gr sz 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: 1_2_3_4_
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 ____ 0.2-3.0µm 200 g.s.=
LIB_SPECTRA: splib06a r ____ 1.5-25µm 250 g.s.=