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Abstract:Quartz crystals containing garnet and rutile inclusions are found in the southwest of Kashan, Iran, adjacent to the Gohrood granitoid intrusive body. This area belongs to the Urmia-Dokhtar magmatic belt, located in the central part of the Iranian plateau with NW-SE trend. The intrusive body related to the garnet and rutile bearing quartzes shows granodiorite-tonalite composition with an age of 17 to 19 million years (Middle Miocene) which has intruded into Jurassic shales, sandstones, limestone, and also cretaceous and Eocene marls which have caused contact metamorphism in surrounding rocks and consequently the formation of typical skarn and hornfels in the area.The studied quartz crystals show size ranges of 1-12 cm which have been formed inside cracks and fractures. The main alteration zones observed in the area consist of silicification, chlorite, epidote associated with hematite, and jarosite mineralization.Different varieties of quartz crystals in terms of color and fluid inclusion characteristics are found in the study area: transparent and semi-transparent crystals, yellow crystals (citrine), dark crystals, smoky to reddish brown crystals (garnet inclusion), and rutile quartz.The carried out fluid inclusion studies indicate that the mean temperature and salinity calculated for the transparent and semi-transparent quartzes are 308 °C and 7.5 wt.% NaCl and 360 °C and 1.6 wt.% NaCl, respectively, and generally, based on the carried out microthermometry studies, the estimated formation temperature ranges between 300-550 °C. The Hydrothermal fluid most likely reached the surface through the faults and joints of Gohrood granitoid with minimal contact with surface fluids, and near the surface mixing with meteoric waters, causing the loss of high temperature and salinity. During rising, these fluids have decomposed the minerals such as biotite, amphibole, and feldspars, which caused the alteration of the wall-rock. The performed microprobe and SEM studies on the inclusions containing garnet in the studied samples show the mineralogical composition of grossular.