A highly pure, replaceable wear insert and a process for manufacturing the same use a group of materials which is suitable for meeting the requirements of high temperature semiconductor technology processes and is chosen at the same time for producing thin layers or components therefrom. The materials are compacted and purified at high temperatures in compression molds and the products so produced are put to their intended use. The substantially thin-walled and crucible-shaped, always highly pure components, which are predominantly made of expanded graphite, are employed as a wear insert for protecting graphitic support crucibles from reactive attack by quartz glass crucibles in semiconductor technology processes at temperatures above 500° C.