Raw expanded vermiculite 1.Size: 0.5-1mm,1-3mm 2-4mm,3-6mm,1-6mm 2.Model: 20-40mesh, 40-60mesh, 60-80mesh, 200 mesh, 325mesh Raw expanded vermiculite Vermiculite is a natural mineral that expands with the application of heat. The expansion process is called exfoliation and it is routinely accomplished in purpose-designed commercial furnaces. Vermiculite is formed by weathering or hydrothermal ...