What is vermiculite and is it asbestos containing?
Vermiculite is the mineralogical name given to hydrated laminar magnesium-aluminum-iron silicate which resembles mica in appearance. All vermiculite ores contain a range of other minerals that were formed along with the vermiculite in the rock. Vermiculite ores from some sources have been found to contain asbestos minerals but asbestos is not intrinsic to vermiculite and only a few ore bodies have been found to contain more than tiny trace amounts. Vermiculite mines are surface operations where ore is separated from other minerals, and then screened or classified into several basic particle sizes. 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). 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. During this
