TITLE: Anorthite GDS28 Plagioclase DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: GDS28

MINERAL_TYPE: Tectosilicate

MINERAL: Anorthite (Plagioclase, Ca end member)(Feldspar group)

FORMULA: CaAl2Si2O8

FORMULA_HTML: CaAl2Si2O8

COLLECTION_LOCALITY: Synthetic

ORIGINAL_DONOR: Bruce Hemingway, USGS

CURRENT_SAMPLE_LOCATION: USGS Reston, VA

ULTIMATE_SAMPLE_LOCATION: USGS Reston, VA

SAMPLE_DESCRIPTION:

The original sample and mid-IR spectrum was described in:

Salisbury, J. W., Walter, L. W., and Vergo, N., 1987, Mid-Infrared (2.1-25µm) Spectra of Minerals: First Edition, U.S. Geological Survey Open File Report 87-263.

From that study, the sample was described as pure.

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

Pure Anorthite.

END_XRD_ANALYSIS.

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


COMPOSITION: SiO2 43.53 wt% SiO2
COMPOSITION: TiO2 0.01 wt% TiO2
COMPOSITION: Al2O3 37.36 wt% Al2O3
COMPOSITION: FeO 0.02 wt% FeO
COMPOSITION: MnO 0.03 wt% MnO
COMPOSITION: MgO 0.03 wt% MgO
COMPOSITION: CaO 19.26 wt% CaO
COMPOSITION: Na2O 0.03 wt% Na2O
COMPOSITION: K2O 0.04 wt% K2O
COMPOSITION: Total 100.32 wt%
COMPOSITION: O=Cl,F,S wt% #correction for Cl, F, S
COMPOSITION: New Total 100.32 wt%

COMPOSITION_TRACE: None

COMPOSITION_DISCUSSION:

Microprobe analysis is the average of 10 analyses. See also: Robie, R.A., Hemingway, B.S., and Wilson, W.H., 1978, American Min., v.63, p. 109-123.

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

The sample appears to be pure anorthite with very fine (cryptocrystalline) texture according to:

Salisbury, J. W., Walter, L. W., and Vergo, N., 1987, Mid-Infrared (2.1-25µm) Spectra of Minerals: First Edition, U.S. Geological Survey Open File Report 87-263. av gr sz = 200um

Abundant vapor bubbles or fluid inclusions, elongate grains somtimes sided by cleavage planes. 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 457 0.2-3.0µm 200 g.s.=200µm

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

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