... Expanded Perlite: 60mesh, 100mesh, 120mesh, 150mesh, 0.1-1mm, 0.5-1.5mm1-2mm, 2-4mm3-6mm 4-8mm Horticultural Perlite ... -1090 ºCMelting point1280-1350 ºC Vickers hardness5.5-7PH6.5-7.5 Water soluble <0.1%Acid soluble <2%Dioptre1.483-1.5063.Chemical ... .54-51-40.34.Perlite features : Poisonless,tasteless,staleless,nonconbustible,acid-resistant,alkali-resistant,Fireproofing,sound proofing ,light weight ,etc ...