Uncle Jack's Ceramic knives are made of an advanced, high-tech ceramic called zirconium oxide (also called zirconia). This material, which is second in hardness only to diamond, was originally developed for industrial applications where metal components failed. Zirconium oxide is extremely hard, wear resistant, and chemically inert. Zirconium oxide has a hardness of 8.2 mohs (vs. steel at 5-6 mohs and diamond at 10 mohs). Cautions: 1. Keep it away from children. 2. Avoid heat or shock 3. Don't cut hard food 4. Do not use your hand to test the hardness of the blade 5. Not for chopping bone, prying, striking. Use bamboo and softer cutting surfaces.