Vermiculite is formed through the disintegration of mica, which liberates lime and takes up water. When vermiculite is heated to 800–1100 C, it divides into thin strips. These release water, curl
up like snakes and swell to become a light porous mass, which can be used as an independent loose insulation or as an aggregate in a lightweight concrete, e.g. in the proportions 6:1 vermiculite to Portland cement [1].