The Yaralujeh vein index is located about 40 km NW of Ahar, East Azarbaijan. The host rock of mineralized vein is an altered subvolcanic body, intermediate in composition. The mineralization of sphalerite-galen-chlcopyrite recognized as intersected veinlets. Based on field observations, textural and mineralogical evidences, the mineralization occurred in 4 stages. The subvolcanic rocks are affected by pervasive sericitc and carbonate alterations and overprinted by supergene assemblages. The plot of the Ishikawa alteration index (AI) Vs. chlorite - carbonate - pyrite index (CCPI), Known as alteration box plot, shows the main alteration species. The assemblage of quartz, sericite, illite, albite, kaolinite, leucoxene, pyrite and late carbonate minerals, indicate the fluids with a near-neutral pH and temperature of approximately 200 to 300 °C. The mineralogical, alteration, and geochemical characteristics of study area in comparison with other hydrothermal deposits indicate that the Yaralujeh vein index is similar to the intermediate-sulfidation epithermal deposits and intermediate  temperature polymetalic veins related porphyry copper deposits