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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: Hydrogrossular NMNH120555 DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: NMNH120555

MINERAL_TYPE: Nesosilicate

MINERAL: Hydrogrossular (Garnet group)

FORMULA: Ca3Al2(SiO4)3-x(OH)4x

FORMULA_HTML: Ca3Al2(SiO4)3-x(OH)4x

COLLECTION_LOCALITY: Rustenberg, South Africa

ORIGINAL_DONOR: National Museum of Natural History

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

Forms series with Grossular.

Sample was sieved to the grain size interval less than 250µm.

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

40 kV - 30 mA, 6.5-9.5 keV
File: hydrg120.out, *.mdi (smear mount on quartz plate)
References: Borg and Smith (1969), JCPDS #10-288, DHZ, v. 1a (1982), Huebner's reference patterns
Found: Garnet; unidentified moderate to weak reflections at 6.0, 4.0, 3.58, 3.23, 3.17, 2.75, 2.59. and 1.76 angstroms.
Sought but not found: anorthite, Fe-oxyhydroxides, ilmenite, apophyllite, prehnite, thaumasite, gehlenite, xonotlite.

Comment: The garnet unit cell dimension ranges more or less continuously from 11.95 to 11.89 angstroms, consistent with grossular-rich members of the grossular-hydrogrossular series. Optically the material consists of colorless, weakly anisotropic garnet and about 10% brownish weakly anisotropic garnet charged with opaque and a few bright red (hematite?)inclusions

J.S. Huebner, J. Pickrell, and T. Schaefer, 1994, written communication.

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 31.44 wt% SiO2
COMPOSITION: TiO2 0.04 wt% TiO2
COMPOSITION: Al2O3 21.40 wt% Al2O3
COMPOSITION: Cr2O3 0.00 wt% Cr2O3
COMPOSITION: V2O3 0.00 wt% V2O3
COMPOSITION: FeO 0.46 wt% FeO
COMPOSITION: NiO 0.00 wt% NiO
COMPOSITION: MnO 0.89 wt% MnO
COMPOSITION: MgO 0.17 wt% MgO
COMPOSITION: CaO 36.14 wt% CaO
COMPOSITION: Total 90.54 wt%
COMPOSITION: O=Cl,F,S wt% #correction for Cl, F, S
COMPOSITION: New Total wt%

COMPOSITION_TRACE:

COMPOSITION_DISCUSSION:

EM analysis by Gregg A. Swayze at the USGS Branch of Geophysics, Denver.

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1b2_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 2229 0.2-3.0µm 200 g.s.=
LIB_SPECTRA: splib05a r 3392 0.2-3.0µm 200 g.s.=


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