Vermiculite << vur MIHK yuh lyt >> is a mineral that occurs as layered flakes. It resembles the mineral mica. Vermiculite consists mainly of the chemical elements aluminum, iron, magnesium, oxygen, and silicon. It may be brown or yellow. When expanded by heat, vermiculite becomes a lightweight, fireproof substance with good heat insulating properties. It is used chiefly in building materials for insulation and soundproofing. It is also used as a soil conditioner and potting material. The United States produces and consumes more vermiculite than any other nation.
See also Mica.
