A ceramic is an inorganic, nonmetallic solid material comprising metal, nonmetal or metalloid atoms primarily held in ionic and covalent bonds. The crystallinity of ceramic materials ranges from highly oriented to semi-crystalline, and often completely amorphous (e.g., glasses). Ceramics are also more chemically resistant and can be used in wet environments where steel bearings would rust. 2  In some cases, their electricity-insulating properties may also be valuable in bearings. 3  Two drawbacks to ceramic bearings are a significantly higher cost and susceptibility to damage under shock loads.