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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: Grossular WS484 Garnet DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: WS484

MINERAL_TYPE: Nesosilicate

MINERAL: Grossular (Grossularite)(Garnet group)

FORMULA: Ca3Al2(SiO4)3

FORMULA_HTML: Ca3Al2(SiO4)3

COLLECTION_LOCALITY: Asbestos, Quebec

ORIGINAL_DONOR: Wards Natural Science Inc.

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

Forms series with Andradite, with Hydrogrossular, with Uvarovite.

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

40 kV - 30 mA, 6.5-9.5 keV
File: gros484.out, *.mdi
References: Borg and Smith (1969), JCPDS #39-368, DHZ, v. 1a(1982), Huebner's reference patterns
Found: Garnet

Comment: Well crystallized reflections indicate good crystallinity and suggest chemical homogeneity. The garnet has ao=11.81 angstroms, consistent with grossular-rich composition.

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 39.710 wt% SiO2
COMPOSITION: TiO2 .253 wt% TiO2
COMPOSITION: Al2O3 22.580 wt% Al2O3
COMPOSITION: Cr2O3 .006 wt% Cr2O3
COMPOSITION: V2O3 .016 wt% V2O3
COMPOSITION: FeO 1.769 wt% FeO
COMPOSITION: NiO .017 wt% NiO
COMPOSITION: MnO .690 wt% MnO
COMPOSITION: MgO .019 wt% MgO
COMPOSITION: CaO 36.170 wt% CaO
COMPOSITION: Total 101.230 wt%
COMPOSITION: O=Cl,F,S wt% #correction for Cl, F, S

COMPOSITION_TRACE: None

COMPOSITION_DISCUSSION:

None.

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

Bimodal grain size distribution:
mode 1: 240 µm @ 75 vol%
mode 2: 15 µm @ 25 vol%

avg. grain size = 210 µm

Trace iron staining. Grains isotropic, with parting, refractive index > glycerin. All consistent with this sample being pure garnet. 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 1868 0.2-3.0µm 200 g.s.= 210 µm
LIB_SPECTRA: splib05a r 2968 0.2-3.0µm 200 g.s.=


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