TITLE: Muscovite GDS111 DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: GDS111

MINERAL_TYPE: Phyllosilicate

MINERAL: Muscovite (Fe-rich)(Mica group)

FORMULA: KAl2Si3O10(OH)2

FORMULA_HTML: KAl2Si3O10(OH)2

COLLECTION_LOCALITY: Guatamala

ORIGINAL_DONOR: Jim Post

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

40 kV - 30 mA, 7.2-9.5 keV
References: Bailey (1984, p. 574), Huebner's reference patterns
Found: dioctahedral mica, 2M1 polytype
Sought but not found: quartz, (100) would be distinct if present

Comments: Very similar patterns. Only mica detected. The mica (004) reflection is at 17.6-17.9 degrees 2 theta; indicating a large alkali such as potassium (the dioctahedral Na-mica, paragonite, has the (004) reflection at 18.4 degrees). The small sample size required smear mounts, which are responsible for a strong preferred basal orientation in each of the patterns. I'd be surprised if you found any differences in the optical spectra of these eight micas."

J.S. Huebner, J. Pickrell, and J. Randow, 1993, written communication.

END_XRD_ANALYSIS.

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


COMPOSITION: SiO2 47.87 wt% SiO2
COMPOSITION: TiO2 0.69 wt% TiO2
COMPOSITION: Al2O3 28.03 wt% Al2O3
COMPOSITION: Fe2O3 7.20 wt% Fe2O3
COMPOSITION: NiO 0.01 wt% NiO
COMPOSITION: MnO 0.07 wt% MnO
COMPOSITION: MgO 0.94 wt% MgO
COMPOSITION: ZnO 0.06 wt% ZnO
COMPOSITION: BaO 0.28 wt% BaO
COMPOSITION: CaO 0.24 wt% CaO
COMPOSITION: K2O 10.16 wt% K2O
COMPOSITION: H2O+ 4.44 wt% H2O+
COMPOSITION: Total 99.99 wt%
COMPOSITION: O=Cl,F,S wt% #correction for Cl, F, S
COMPOSITION: New Total wt%

Jim Post, personnal communication, 1991.

COMPOSITION_TRACE:

COMPOSITION_DISCUSSION:

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

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 3276 0.2-3.0µm 200 g.s.=

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

LIB_SPECTRA: splib06a r ____ 1.5-25µm 250 g.s.=