<abstract xmlns="http://www.w3.org/1999/xhtml">The green colour of prasiolite, defined as naturally occurring transparent macrocrystalline α-quartz with primary colouration, results from the optical absorption centred at ~13,660 cm−1 and attributed to the FeVI2+→FeVI3+ intervalence charge transfer (<xref ref-type="bibr" rid="j_mipo-2016-0004_ref_016_w2aab2b8b5b1b7b1ab1ac16Aa">Platonov et al. 1992</xref>). However, optical absorption spectroscopy of blue-green to green quartz from Rakowice Wielkie, Sudetes, south-western Poland, shows that its primary colouration results from the combination of this band and absorptions at ~18,500 cm−1 and ~16,250 cm−1. The first is assigned to a hole centre Fe4+s(Fe3+s-e−) combined with an electron centre Fe2+I6(Fe3+I6+e−), while the second from AlO44− defects. The quartz is blue-green if the 18,500 cm−1 prevails and becomes pale green if the 16,250 cm−1 band predominates. These colours seem to represent intermediate colour varieties between amethyst and prasiolite. We also suggest that spectral features of coloured quartz varieties might be useful indicators of changes in the physical- and chemical characteristics of the mineral-forming fluids.</abstract>

The green colour of prasiolite, defined as naturally occurring transparent macrocrystalline α-quartz with primary colouration, results from the optical absorption centred at ~13,660 cm−1 and attributed to the FeVI2+→FeVI3+ intervalence charge transfer (Platonov et al. 1992). However, optical absorption spectroscopy of blue-green to green quartz from Rakowice Wielkie, Sudetes, south-western Poland, shows that its primary colouration results from the combination of this band and absorptions at ~18,500 cm−1 and ~16,250 cm−1. The first is assigned to a hole centre Fe4+s(Fe3+s-e−) combined with an electron centre Fe2+I6(Fe3+I6+e−), while the second from AlO44− defects. The quartz is blue-green if the 18,500 cm−1 prevails and becomes pale green if the 16,250 cm−1 band predominates. These colours seem to represent intermediate colour varieties between amethyst and prasiolite. We also suggest that spectral features of coloured quartz varieties might be useful indicators of changes in the physical- and chemical characteristics of the mineral-forming fluids.

Green to blue-green quartz from Rakowice Wielkie (Sudetes, south-western Poland) – a re-examination of prasiolite-related colour varieties of quartz

Institute of Geochemistry, Mineralogy and Ore Formation, Academy of Science of Ukraine, Palladina 34, 252 680 Kiev-142,

Institute of Geological Sciences, University of Wrocław, 50-204 Wrocław, pl. M. Borna 9,

Mineralogia

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

The green colour of prasiolite, defined as naturally occurring transparent macrocrystalline α-quartz with primary colouration, results from the optical...

Green to blue-green quartz from Rakowice Wielkie (Sudetes, south-western Poland) – a re-examination of prasiolite-related colour varieties of quartz

Publié en ligne: 18 févr. 2017

Pages: 19 - 28

Reçu: 09 mars 2016

Accepté: 26 mai 2016

DOI: https://doi.org/10.1515/mipo-2016-0004

Mots clés
prasiolite, green quartz, optical absorption, Rakowice Wielkie, Sudetes

© 2015 Alexej N. Platonov et al., published by De Gruyter Open

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Green to blue-green quartz from Rakowice Wielkie (Sudetes, south-western Poland) – a re-examination of prasiolite-related colour varieties of quartz

Publié en ligne: 18 févr. 2017

Pages: 19 - 28

Reçu: 09 mars 2016

Accepté: 26 mai 2016

DOI: https://doi.org/10.1515/mipo-2016-0004

Mots clésprasiolite, green quartz, optical absorption, Rakowice Wielkie, Sudetes

© 2015 Alexej N. Platonov et al., published by De Gruyter Open

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Mots clés
prasiolite, green quartz, optical absorption, Rakowice Wielkie, Sudetes