... Specifications Characteristics Chemical Compositions Physical Features Diameter Ranges (mm) G-J-I Popular Type Economy grinding medium,suits for grinding of ... .5g/ cm³ Microhardness:≥680kg/mm² 0.8-4.0 G-J-III Wearproof TypeZirconia Glass Drops Big specific density,highintensity,low ... .65g/ cm³ Microhardness:≥720kg/mm² 0.8-4.0 G-J-IV Bright White Type Colorless,transparent,highintensity,low wear,used ...