vermikulite

Vermiculite is a hydrated laminar magnesium-aluminum-iron silicate mineral. It belongs to the phyllosilicate group of minerals, specifically the mica group, although it is not a true mica. When heated to high temperatures, vermiculite undergoes exfoliation, expanding into a lightweight, accordion-like material. This expansion is due to the water trapped between the layers of the mineral turning to steam and forcing the layers apart.

The exfoliated form of vermiculite is characterized by its low density, excellent water retention, and inertness. These properties make it useful in a variety of applications. In horticulture, it is widely used as a soil amendment to improve aeration, drainage, and moisture retention in potting mixes and garden soils. It can also be used as a medium for seed germination and hydroponic growing systems.

Beyond gardening, vermiculite has found industrial applications as insulation, fireproofing material, and as a component in lightweight cements and plasters. Its ability to absorb and release moisture also makes it useful in packaging, particularly for fragile items and for the transport of live organisms. The mineral is typically mined from deposits and then processed through heating to achieve its characteristic expanded form.