Kyocera ceramic knives are made of an advanced, high-tech ceramic called zirconium oxide. This material, which is second in hardness only to diamond, was originally developed for industrial applications where metal components failed. It is extremely hard, wear resistant, and chemically inert. This results in knives that keep their edge and can go months or years without sharpening, do not react with the food that is being prepared, are easy to clean and easy to use.