Modes of occurrence of Au-and Ag-bearing phases and their relation with associated hypogene ore minerals were examined with the objective to elucidate Au-Ag distribution at the Esperanza porphyry deposit in the Eocene Centinela copper belt, using ore-microscope modal analysis, semi-quantitative analyses by automated mineralogy, electron probe microanalysis, and secondary ion mass spectrometer. The Esperanza hypogene mineralization is characterized by early-stage chalcopyrite-rich veinlets in the potassic alteration zone and later polymetallic stage with tennantite and galena in the chlorite-sericitic alteration zone. Only the early-stage chalcopyrite contains fine-grained electrum (Au 68 Ag 32-Au 81 Ag 19) and hessite (Ag 2 Te), and thus yields positive correlations in Cu vs. Au and Cu vs. Ag grades that are clearly recognized in the hypogene sulfide zone. The early-stage chalcopyrite grains frequently exhibit polysynthetic twinning suggestive of inversion from intermediate solid solution. These features suggest that the fine-grained electrum and hessite are products exsolved in the cooling process with the intermediate solid solution to chalcopyrite inversion. In contrast, tennantite and galena of the later-stage mineralization contain no detectable Ag, and it is thus proposed that the earlystage inverted chalcopyrite is the principal storage of economically important precious metals. K E Y W O R D S chalcopyrite, Cu-Au correlation, electrum, Esperanza porphyry deposit, microanalyses 1 | INTRODUCTION Most Cordillera-type porphyry deposits were traditionally regarded as Cu-or Cu-Mo-type (Kesler, 1973; Vila and Sillitoe, 1991; Kesler et al., 2002). The Au-rich character is frequently represented in the island arc-type porphyry copper deposits and related high-sulfidation epithermal deposits, to which systematic data on precious metal mineralogy, including microanalytical studies of common sulfide minerals, have been reported (e.g., Kesler et al., 2002; Arif and Baker, 2004; Bunce et al., 2015). Nevertheless, detailed studies on precious metal mineralogy have not yet been made for porphyry deposits in the Andean Cordillera, in which Au-bearing ores occasionally occur: e.g.,