Sample Description USGS Spectral Library Version 7

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
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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.

IMAGE_OF_SAMPLE:

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