MINERALS FROM MACEDONIA. XI. THE DEPENDANCE OF QUARTZ AND OPAL COLOR ON THE TRACE ELEMENT COMPOSITION - AAS, FT IR AND MICRO-RAMAN SPECTROSCOPY STUDY (original) (raw)

The dependence of the color of quartz and opal natural minerals, collected from different localities in the Re- public of Macedonia (Alinci, Belutče, Budinarci, Mariovo, Sasa, Saždevo, Čanište, Češinovo, Zletovo) on their ele- ment composition is studied using Fourier transform infrared spectroscopy (FT IR), micro-Raman spectroscopy and atomic absorption spectrometry (AAS). In order to determine the content of different trace elements (Al, Cd, Ca, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb and Zn), 15 quartz and 2 opal mineral samples, using flame atomic absorption spectrometry (FAAS) and Zeeman electrothermal atomic absorption spectrometry (ETAAS) are studied. To avoid matrix interferences, the method for elimination of silicium is proposed. Optimal instrumental parameters for ETAAS determination (temperature and time for drying, pyrolysis and atomizing) are established by extensive test- ing for each investigated element. It is found that the milky white color of quartz minerals is due...