<；P>；PROBLEM TO BE SOLVED: To provide gravel or formed gravel having good adhesion efficiency of bacteria and excellent in water purification ability and excellent in water permeability, by effectively using an end material or a grinding waste generated at the time of processing of a Kimachi stone or a defective stone. <；P>；SOLUTION: A working waste such as the end material or the grinding waste or the like of the Kimachi stone or the defective stone is crushed so as to obtain angular rubble or semi-angular rubble. The crushed rubble is fired at the temperatures of 800°；C to 1,180°；C so as to obtain a fired gravel material made of the Kimachi stone having a number of micropores. Furthermore, a formed fired gravel material made of the Kimachi stone is obtained by firing a granular molding formed by adding water to a Kimachi stone powder at the temperatures of 800°；C to 1,180°；C. <；P>；COPYRIGHT: (C)2006,JPO&NCIPI
