Material witness: call yourself hard?
Ball
Philip
P
D001896:Boron Compounds / Q000032:analysis / Q000737:chemistry*; D018130:Diamond / Q000032:analysis / Q000737:chemistry*; D006244:Hardness; D008422:Materials Testing; D008903:Minerals / Q000032:analysis / Q000737:chemistry*
D001896:Boron Compounds; D008903:Minerals; C017282:boron nitride; D018130:Diamond