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Clark et. al. 2003 USGS Open File Report 03-395
Spectral Library splib05a Sample Description

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

TITLE: Andradite NMNH113829 Garnet DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: NMNH113829

MINERAL_TYPE: Nesosilicate

MINERAL: Andradite (Garnet group)

FORMULA: Ca3(Fe+3)2(SiO4)3

FORMULA_HTML: Ca3Fe+32(SiO4)3

COLLECTION_LOCALITY: Rimpfischwange, Zermitt, Valais, Switzerland

ORIGINAL_DONOR: Smithsonian

CURRENT_SAMPLE_LOCATION: USGS Reston, VA.

ULTIMATE_SAMPLE_LOCATION: USGS Reston, VA.

SAMPLE_DESCRIPTION:

Forms series with Grossular and with Schorlomite.

The original sample description and mid-infrared spectrum was published 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.

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

Hand-picked sample is pure andradite. From:

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.

Specific XRD analysis says pure Andradite - by Norma Vergo

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 35._50 wt% SiO2
COMPOSITION: TiO2 0.07 wt% TiO2
COMPOSITION: Al2O3 0.29 wt% Al2O3
COMPOSITION: FeO 28.17 wt% FeO
COMPOSITION: MnO 0.11 wt% MnO
COMPOSITION: MgO 0.14 wt% MgO
COMPOSITION: CaO 33.11 wt% CaO
COMPOSITION: Na2O 0.02 wt% Na2O
COMPOSITION: K2O 0.01 wt% K2O
COMPOSITION: Total 97.42 wt%
COMPOSITION: O=Cl,F,S wt% #correction for Cl, F, S
COMPOSITION: New Total 97.42 wt%

COMPOSITION_TRACE: None

COMPOSITION_DISCUSSION:

The above analysis was an average of 8 analyses and indicates nearly end-member composition. The analysis shows the sample is homogenous within and between grain boundaries.

From: 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.

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

The following description is from: 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.

"The sample is a cluster of subhedral crystals, green in color varying slightly with shade. Some grains are coated with a white contaminant that is soft. Dark impurities can be seen in the microscope. The white contaminant does not disappear with HCl treatment. The sample was crushed to free individual 3mm crystals and the clean bright green crystals hand picked. A few grains have a light brownish tinge on some edges. The microprobe grains appeared pure."

avg. grain size = 200µm

Clear pure grains, conchoidal fracture, isotropic under cross-polarized light. G. Swayze

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1a2_3_4_ # 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 390 0.2-3.0µm 200 g.s.=
LIB_SPECTRA: splib05a r 999 0.2-3.0µm 200 g.s.=


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