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USGS Spectral Library Version 7 Sample Description

Kokaly, R.F., Clark, R.N., Swayze, G.A., Livo, K.E., Hoefen, T.M., Pearson, N.C., Wise, R.A., Benzel, W.M., Lowers, H.A., Driscoll, R.L., and Klein, A.J., 2017, USGS Spectral Library Version 7: U.S. Geological Survey Data Series 1035, 61 p., https://doi.org/10.3133/ds1035
For more information on the library, see: local link web link

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.

IMAGE_OF_SAMPLE:
Photo of sample

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