Du-Co Ceramics Du-Co Ceramics Company™ is a fully integrated technical ceramics manufacturer complete with a Ceramic Engineering Department, Tool and Die Facility, Development Labs, and Up-to-Date Quality Programs. We produce ceramic parts in Steatite, Cordierite, Magnesium Oxide, Alumina, Mullite and Forsterite . Du-Co Ceramics Company’s processes are dry pressing, extrusion, secondary machining, glazing, and both centerless and flat grinding.