Ceramic knives are made from zirconium oxide, which is harder than steel. Home and professional cooks prize ceramic knives for their extraordinary sharpness and durability. Proper care and handling will make your knife a faithful kitchen servant for years to come.
Ceramic knives are exceptionally hard and slice right through fruits, vegetables and meats. Do not attempt to cut through bone, hard cheese -- such as aged Parmesan -- nuts or frozen items. Use a ceramic knife for food products only -- cutting through tin cans or cardboard could compromise the edge; twisting the knife could snap the handle. Avoid using glass, stone or marble cutting boards, and instead opt for wood, plastic and bamboo, which are softer on the knife's edge.
Wash your ceramic knife by hand with soapy water and dry it with a kitchen towel. Avoid using harsh scrubbers, such as steel wool, to clean the knife. You risk damaging the edge of the knife if you put it into the dishwasher, because the agitation of cleaning might bump it into other objects. The dishwasher's heat could also degrade the glue used to bond some blades to their handles.
Your ceramic knife likely came with a protective sheath for storage. Keeping it in this sheath prevents it from banging into steel knives or other hard objects in drawers and potentially chipping the edge. You could also store your knife in a wooden or bamboo knife block; avoid acrylic versions, which are not optimal for ceramic storage.
Ceramic knives maintain their sharpness longer than steel knives and rarely need sharpening. Some manufacturers offer a knife-sharpening service when your knife blade does become dull or chipped. Professional knife sharpeners use a diamond sharpener for ceramic knives. These are available for home use, but you'll guarantee a better result from a professional service. Avoid using traditional sharpening stones or steels -- these aren't designed for ceramic knives.