A ceramic knife is a knife made out of very hard ceramic, often zirconium oxide (ZrO2; also known as zirconia). These knives are usually produced by compacting zirconia powder using high pressure presses which apply a pressure of around 300 tons to produce blade-shaped blanks. These blanks are very brittle and fragile and can be shattered by a slight blow; special binders are used to retain the shape of the blank until the firing process. Like most ceramics these are consolidated into a dense and strong ceramic by solid-state sintering at approximately 1400 degrees

Celsius for 5–12 hours in a high-temperature furnace. The result is a very hard and blunt blade which is then sharpened by grinding the edges with a diamond-dust-coated grinding wheel. Ceramic blades can only be resharpened with a material harder than themselves; industrial grade diamond sharpeners are usually used. Ceramic knives will not rust, they are also nonconductive and nonmagnetic. Their chemical inertness to both acids and alkalis and their ability to retain a cutting edge far longer than forged metal knives makes them a very good culinary tool for slicing and cutting through boneless meat, vegetables and fruits. Since they are very brittle they cannot be used for chopping, cutting bones or frozen foods or for any application which tends to twist the blade such as prying, which may cause the cutting edge to chip or the blade to break free from the handle. The tips of these knives are resistant to rolling and pitting, but may break if dropped.