Vermiculite is a mica-like mineral which exfoliates (expands or “pops” upon rapid heating) to produce an inert, low-density material with significant thermal qualities – it does not burn and provides excellent heat resistance.

Vermiculite has been used in various industries. It is used in the construction, agricultural, horticultural, and industrial markets. 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 .

This characteristic of exfoliation, the basis for commercial use of the mineral, is the result of the mechanical separation of the layers by the rapid conversion of contained water to steam. The increase in bulk volume of commercial grades is 8 to 12 times, but individual flakes may exfoliate as many as 15 times. There is a color change during expansion that is dependent upon the composition of the vermiculite and furnace temperature.