摩氏(shi)硬度(du)10,新摩氏(shi)硬度(du)15,顯微(wei)硬度(du)10000kg/mm2,顯微(wei)硬度(du)比石(shi)英高1000倍,比剛玉高150倍。金(jin)剛石(shi)硬度(du)具(ju)有方向性,八面(mian)(mian)體(ti)(ti)(ti)晶面(mian)(mian)硬度(du)大于菱形十(shi)(shi)二面(mian)(mian)體(ti)(ti)(ti)晶面(mian)(mian)硬度(du),菱形十(shi)(shi)二面(mian)(mian)體(ti)(ti)(ti)晶面(mian)(mian)硬度(du)大于六面(mian)(mian)體(ti)(ti)(ti)晶面(mian)(mian)硬度(du)。
依照摩(mo)氏(shi)硬(ying)度標準(Mohs hardness scale)共分10級(ji),鉆石(金剛石)為(wei)最高級(ji)第10級(ji);如小(xiao)刀其硬(ying)度約為(wei)5.5、銅(tong)幣約為(wei)3.5至4、指(zhi)甲約為(wei)2至3、玻璃硬(ying)度為(wei)6。