Bačík P., Fridrichová J., Štubňa J. & Antal P., 2015: Application of spectroscopic methods in mineralogical and gemmological research of gem tourmalines. Acta Geologica Slovaca, 7, 1, 1–9.

Application of spectroscopic methods in mineralogical and gemmological research of gem tourmalines

Využitie spektroskopických metód v mineralogickom a gemologickom výskume drahokamových turmalínov

Peter Bačík¹ , Jana Fridrichová¹ , Ján Štubňa² & Peter Antal³

¹Department of Mineralogy and Petrology, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynská dolina, Ilkovičova 6, 842 15 Bratislava, Slovakia; bacikp@fns.uniba.sk
²Institute of Gemmology, Faculty of Natural Sciences, Constantine the Philosopher University in Nitra, Nábrežie mládeže 91, 949 74 Nitra, Slovakia
³Department of Inorganic Chemistry, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynská dolina, Ilkovičova 6, 842 15 Bratislava, Slovakia

Abstract

Faceted tourmaline gemstones obtained from commercial sources as elbaites were studied with non-destructive spectroscopic methods. We applied Raman spectroscopy for mineral identification and UV/Vis/NIR spectroscopy for determination of chromophores. We identified the most of samples as fluor-elbaite to elbaite by Raman spectroscopy except one sample which has likely fluor-dravitic to fluor-uvitic composition. In green elbaitic tourmalines divalent iron is the most significant chromophore. Yellow-green and pink elbaitic tourmaline are coloured by Mn in divalent and trivalent form, respectively. The green colour of dravitic to uvitic tourmaline is the result of absorption caused by V.

Key words: tourmaline, gemmology, chromophore, Raman spectroscopy, UV/Vis/NIR spectroscopy

Manuscript received: 2014-08-18

Revised version accepted: 2015-03-25