A member of supporting magnetic disc substrates is provided, comprising a ceramic sinter containing a ceramic component and at least one conductive component selected from a group consisting of iron, niobium, tin zinc, copper, nickel, cobalt, and chromium, wherein the ceramic sinter has conductive aggregates on its peripheral surface. In the member, the ceramic component may be forsterite and the conductive component is iron oxide, wherein the ceramic sinter comprises a main phase of 2MgO.SiO.sub.2 and a secondary phase of at least one of MgFe.sub.2O.sub.4, Fe.sub.3O.sub.4, and Fe.sub.2O.sub.3. The ceramic sinter can be produced by a process including: sintering a ceramic sinter from a ceramic component and at least one conductive component selected from a group consisting of iron, niobium, tin zinc, copper, nickel, cobalt and chromium; machining the sinter into a desired shape of a member of supporting a magnetic disc substrate, and annealing the sinter such that the ceramic sinter has conductive aggregation deposited on its peripheral surface, wherein in the annealing step, the member is heated at a temperature in between a glass transition temperature of the sinter minus 500.degree. C. and a softening temperature of the sinter plus 600.degree. C.