... Basically, they're made out of a high-purity zirconium oxide powder that is compressed at ... as diamonds. Features: 1.Special Materials: Using high-tech Zirconia crafted, high-density, high hardness, never wear, hardness (HRA87) is ... ! 3.Excellent performance: because of its extremely high density and bright the knife is not easy ... ceramic knife to cut it high tech and fashion 4pcs ceramic knife set