Hydrogrossular

Spectrum Details

Modality

FTIR

Category

mineral

Material Type

Nesosilicate

Sample ID

NMNH120555

Collection Locality

Rustenberg, South Africa

Spectral Purity

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

Composition / XRD

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%

Sample Description

Forms series with Grossular. Sample was sieved to the grain size interval less than 250µm. IMAGE_OF_SAMPLE:

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.

X Units

cm⁻¹

Y Units

Absorbance

Data Points

1,801