Fire clay of the Kabutarkuh deposit, located about 50 km southeast of Gonabad (Khorasan Province), was analyzed for its mineralogical and chemical compositions. Kaolinite, pyrophilite, quartz, dickite, gypsum, illite and alunite are the dominant minerals, and a minor phase of hematite is also present. Geochemical data show that the whole rock sample is mainly composed of SiO2, Al2O3 and K2O. Ch...