The parisite–(Ce) enigma:

Author(s)
M. Zeug, L. Nasdala, M. Ende, G. Habler, Ch. Hauzenberger, C. Chanmuang N., R. Škoda, D. Topa, M. Wildner, R. Wirth
Abstract

A multi-methodological study was conducted in order to provide further insight into the structural and compositional complexity of rare earth element (REE) fluorcarbonates, with particular attention to their correct assignment to a mineral species. Polycrystals from La Pita Mine, Municipality de Maripi, Boyaca Department, Colombia, show syntaxic intergrowth of parisite-(Ce) with rontgenite-(Ce) and a phase which is assigned toB(3)S(4)(i.e., bastnasite-3-synchisite-4; still unnamed) fluorcarbonate. Transmission electron microscope (TEM) images reveal well-ordered stacking patterns of two monoclinic polytypes of parisite-(Ce) as well as heavily disordered layer sequences with varying lattice fringe spacings. The crystal structure refinement from single crystal X-ray diffraction data - impeded by twinning, complex stacking patterns, sequential and compositional faults - indicates that the dominant parisite-(Ce) polytypeM(1)has space groupCc. Parisite-(Ce), theB(3)S(4)phase and rontgenite-(Ce) show different BSE intensities from high to low. Raman spectroscopic analyses of parisite-(Ce), theB(3)S(4)phase and rontgenite-(Ce) reveal different intensity ratios of the three symmetric CO(3)stretching bands at around 1100 cm(-1). We propose to non-destructively differentiate parisite-(Ce) and rontgenite-(Ce) by their 1092 cm(-1)/ 1081 cm(-1)nu(1)(CO3) band height ratio.

Organisation(s)
Department of Mineralogy and Crystallography, Department of Lithospheric Research
External organisation(s)
Karl-Franzens-Universität Graz, Masaryk University, Naturhistorisches Museum Wien (NHM), Helmholtz-Zentrum Potsdam Deutsches GeoForschungsZentrum
Journal
Mineralogy and Petrology
Volume
115
Pages
1-19
No. of pages
19
ISSN
0930-0708
DOI
https://doi.org/10.1007/s00710-020-00723-x
Publication date
02-2021
Peer reviewed
Yes
Austrian Fields of Science 2012
104026 Spectroscopy, 105116 Mineralogy, 105113 Crystallography
Keywords
ASJC Scopus subject areas
Geochemistry and Petrology, Geophysics
Portal url
https://ucrisportal.univie.ac.at/en/publications/500b1313-0918-4b0e-babf-b37b27913f82