vermiculite
Isaac Kremer/ January 14, 2018/ / 0 comments
A hydrated magnesium-aluminum-iron silicate which is a micaceous material that exfoliates when heated, splitting into thin laminae, and with further heating into long wormlike pieces. The exfoliated material is used to fill insulation, in place of sand in gypsum plaster, and as an aggregate in light-weight concrete and acoustical plaster. (Saylor, 1952)