... 1.5mm1-2mm, 2-4mm3-6mm 4-8mm Horticultural Perlite: 1-2mm, 2-4mm, 1-4mm ,3-5mm.4-8mmSpecial size is supplied ... 7PH6.5-7.5 Water soluble <0.1%Acid soluble <2%Dioptre1.483-1.5063.Chemical properties CompositionAl2O3SiO2Fe2O3CaONa2OK2OMaOPercentage12-1668- ... 51-40.34.Perlite features : Poisonless,tasteless,staleless,nonconbustible,acid-resistant,alkali-resistant,Fireproofing,sound proofing ,light weight , ...