Zirconia diamond is a high temperature synthetic cut stone made from Zirconia by Russian scientist in 1975. JOHNCERA Ceramic Knife and Ceramic Peeler are also made from zirconium oxide, one of the highest quality ceramic materials which is second to diamond in hardness. The knife peeler are mainly used for fruit and vegetable cutting. This high-tech Knife and peeler are produced by same manufacture craft, high temperature synthetic. Due to the advantage of ceramic knife, such as sharp for ever, avoid the stain from juice of food, corrosion resistant, no metallic taste and smell and so on, JOHNCERA Ceramic Knife is very popular in home and foreign market.