Spectroscopic properties of halite from Kłodawa salt mine, central Poland

• Published in: Mineralogy and petrology 2015, Vol.109 (1), p.45-51
• Main Authors: Zelek, Sylwia M., Wesełucha-Birczyńska, Aleksandra, Szklarzewicz, Janusz, Stadnicka, Katarzyna M.
• Format: Article
• Language: English
• Subjects: Earth and Environmental Science; Earth Sciences; Geochemistry; Inorganic Chemistry; Mineralogy; Original Paper
• ISSN: 0930-0708; 1438-1168
• DOI: 10.1007/s00710-014-0348-0

The dynamics of colour centre transformation was investigated in blue halite single crystals from Kłodawa Salt Mine, Central Poland, using UV–vis spectroscopy. The following colour centres were considered: F, R 1 , R 2 , as well as plasmons and M centres. The R 2 centres predominated in navy blue (A) and pale blue (B) halites. Other relatively large populations were plasmons found in all examined samples. In purple (C) halite samples the plasmon population is the highest one among others and R 1 centres appeared to be equally significant, whereas M centres were almost absent. For A and C samples unidentified bands were observed at 26,500 to 26,200 cm −1 , respectively. The bleaching process of the blue halites was investigated using temperature dependent UV–vis and micro-Raman spectroscopies. In micro-Raman 300–100 cm −1 region three very intense sharp bands were attributed to the colour centres and colloidal Na precipitation in A and B halites. The one broad band in the range 3,500 to 500 cm −1 , which was characteristic even for the colourless sample D but absent in the spectra of colourless NaCl obtained after recrystallization of sample A, requires further study.