Chemical composition of white micas from the Elatsite porphyry copper deposit, Bulgaria

White mica (sericite) is one of the most common minerals in the hydrothermal alteration types at the Elatsite deposit. Differences in the mineral chemistry of sericite revealed some characteristics of the hydrothermal fluid environment. Lowest values of phengite component are determined in sericite from quartz-sericitic alteration, while higher phengite component with lower values for Na2O are reported in sericite from quartz-adularia-carbonate alterations. This probably reflects lower temperature formation from fluids with relatively high pH (close to the neutral) for sericite from quartz-adularia-carbonate alteration compared to this from quartz-sericitic alteration.