Annite

Spectrum Details

Modality

NIR

Category

mineral

Material Type

Phyllosilicate

Sample ID

WS661

Collection Locality

Faraday, Ontario, Canada

Spectral Purity

1b2b3b4_ # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns

Composition / XRD

EPMA # XRF, EPMA, 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%

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:

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 Konnert, Judith and Marta Flohr, 1992, unpublished data, USGS Reston, VA. 40 kV - 30 mA, 7.3-9.5 keV File: annit661.out, -.mdi (smear mount on quartz plate) References: Huebner's reference patterns Found: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)

X Units

cm⁻¹

Y Units

Absorbance

Data Points

2,126