Flint clay is a representive of Chinese refractory clay. Normally, flint clay means CALCINED FLINT CLAY, it is calcined clay ore. Its Al2O3 content is about 44%, Fe2O3 less than 2%, with stable compound and dense structure,fracture surface likes broken shells. Flint clay has no fixed compound. It is like Kaolin clay (Al2O3/3SiO2=0.85), besides some free quartz, it also has very few ferro and alkalis mineral. Common color include: pure white, light gray, light tea-yellow, some are brown. Flint clay has refractoriness and sinterability. This compound of many aluminum silicate , main component is Al2O3 and SiO2. Oxide impurities will flux the material, lower its refractoriness. Lower the Na2O+K2O content, higher the refractoriness. As Al2O3/3SiO2 ratio near theoretical value(A/S= 0.85), flint clay is purer, refractoriness is higher, and its sinterablity is better .Top grade fint clay can reach 1750 refractoriness, water absorbtion less than 5%, bulk density bigger than 2.55g/cm3.