... Particle shape even into the water caltrop crystals have sharp edges, grinding force high hardness of 7-8 ... efficiency pomegranate sand, in a certain pressure to quickly with sharp edges and corners impact surface, so it was ... as copper slag, nickel slag, etc.) rough sharp edges and corners in the spray easily left in ... volume density 3.96-4.10g/cm3, melting point of 1180-1280 °C, Mohs hardness of 7. ...