Vermiculite is a member of the phyllosilicate group of minerals, resembling mica in appearance. It is found in various parts of the world, vermiculite is basically a hydrated phlogopite mica which has the remarkable ability to expand to many times its original volume when heated at 850 -1100°C.Crude vermiculite consists of golden and silver vermiculite which are carefully classified into many sizes ,includes0.3-1mm1.5-2.5mm0.5-1.41mm1-2mm2-4mm3-6mm4-8mm.