Graphite blocks are produced by a process wherein one or plural polymer films having a thickness of from 1 to 400 mu m and selected from aromatic polyimides, aromatic polyamides and polyoxadiazoles are heat treated to obtain carbonaceous films. A plurality of the carbonaceous films are hot pressed under certain conditions to obtain thick graphite blocks. The blocks have a remarkably improved rocking characteristic and are useful as radiation optical elements such as X-ray or neutron ray monochromators or filters. The blocks may be curved to obtain bent-type graphite articles.
