The effect of chemical variability and weathering on Raman spectra of enargite and fahlore

Abstract. Enargite (Cu3AsS4) and tennantite (Cu12As4S13) are typical As-bearing sulfides in intermediate- high-sulfidation epithermal deposits. Trace major element variations enargite their substitution mechanisms widely described. However, Raman spectra of the minerals with correlative quantitative chemical information rarely documented, especially for enargite. Therefore, comparative electron μ-Raman microprobe analyses were performed on fahlore grains. These can be used industrial detection subsequent removal prior to ore beneficiation order diminish environmental impact metallurgical technologies. A simple Sb5+–As5+ was confirmed by analyses. Similarly, a complete solid solution series from tetrahedrite (i.e., Sb3+–As3+ substitution) correlated gradual evolution spectra. In turn, Te4+ occupies As3+ Sb3+ sites coupled + Cu+ → (As, Sb)3+ (Cu, Fe, Zn)2+. Accordingly, bands goldfieldite (Te-rich member) strongly broadened compared those tennantite. secondary phase high porosity fibrous or wormlike texture found weathered sample. The composition, spectrum, X-ray diffraction signature resemble transformation primary into this visualized mapping.