Spectroscopic study of inclusions in gem corundum from Mercaderes, Cauca, Colombia

Author(s)
Manuela Zeug, Andrés Ignacio Rodríguez Vargas, Lutz Nasdala
Abstract

Mineral inclusions in gem corundum from Mercaderes, Cauca, Colombia, were investigated non-destructively using Raman and photoluminescence spectroscopy, with special focus lying on phases containing radioactive elements. Besides abundant rutile, the minerals zircon, apatite, feldspar, and an epidote-group species, most probably allanite–(Ce), were found. The latter is detected easily from its characteristic Nd

3+emission pattern, which may prove useful in future provenance studies. Zircon inclusions range from well crystalline to moderately radiation damaged [FWHM (full width at half band maximum) of the ν

3(SiO

4) Raman band 1.8–10.9 cm

−1]. Both the zircon inclusions and their neighbouring host corundum are affected by compressive stress, which is assigned to (1) heterogeneous volume expansion of the host-inclusion couple upon pressure release during the uplift following primary growth and (2) volume expansion of the zircon inclusion due to the accumulation of self-irradiation damage. Internal stress of zircon inclusions averages ~1.1 GPa. Heat treatment of corundum leads to structural reconstitution of zircon (narrowed zircon Raman bands with FWHMs in the range 1.8–2.7 cm

−1) and accompanying stress release in the adjacent corundum (indicated by downshifts of the R

1emission of Cr

3+). The observation of broadened Raman band of zircon inclusions therefore allows one to exclude high-temperature enhancement of the host corundum.

Organisation(s)
Department of Mineralogy and Crystallography
External organisation(s)
Minerlab Limitada, Bogota
Journal
Physics and Chemistry of Minerals
Volume
44
Pages
221-233
No. of pages
13
ISSN
0342-1791
DOI
https://doi.org/10.1007/s00269-016-0851-4
Publication date
10-2016
Peer reviewed
Yes
Austrian Fields of Science 2012
104026 Spectroscopy, 105116 Mineralogy
Keywords
ASJC Scopus subject areas
Geochemistry and Petrology, General Materials Science
Portal url
https://ucrisportal.univie.ac.at/en/publications/2e1ea09d-b7e5-4979-ba5c-d8ca68315790