Vermiculite is the mineralogical name given to hydrated laminar magnesium-aluminum-iron silicate which resembles mica in appearance.
When subjected to heat vermiculite has the unusual property of exfoliating or expanding into worm-like pieces - the name vermiculite is derived from the Latin vermiculare - to breed worms. But in practice, it can include any of a group of hydrous silicates of mica, used as heat-insulation, etc. |
