... 50-70mesh, 70-90mesh, 90-120mesh, 120-200mesh 325mesh Expanded Perlite: 60mesh, 100mesh, 120mesh, 150mesh, 0.1-1mm, 0.5-1.5mm1-2mm, 2 ... -4mm3-6mm 4-8mm Horticultural Perlite: 1-2mm, 2-4mm, 1-4mm ,3-5mm ... ºC Vickers hardness5.5-7PH6.5-7.5 Water soluble <0.1%Acid soluble <2%Dioptre1.483-1.5063.Chemical properties CompositionAl2O3SiO2Fe2O3CaONa2OK2OMaOPercentage12 ...