Perlite - (French perlite, perle — pearl) — a rock of volcanic origin
At the edge of lava flow, in places of initial contact of magmatic melts and earth surface, quick magma chilling leads to formation of volcanic glass - obsidian. Further, underground water penetrates obsidian, causing its hydration and formation of obsidian hydroxide - perlite.
Perlite is a non-fibrous material and is totally safe for humans, causing no allergy and skin irritation and no harmful impact on indoor climate. It is very easy to handle – it’s easy to fill cavities in walls and corners with. This material is non-combustible, rot-resistant, biostable and chemically inert (PH=6.5±7). Due to these unique properties of perlite, it is widely used in construction industry.
Perlite is characterized by fine concentric shell-like cleavage (perlitic structure) by which it disintegrates into separate round cores (pearls) resembling pearls with characteristic luster. Perlite is distinguished among other volcanic rocks by the presence of combined water (over 1 %). Porosity may be 8-40%.
Perlite may be black, green, red-brown, brown and white, with various shades.
Varieties of perlite: obsidian (with obsidian admixtures) perlite, spherulitic perlite (with feldspar admixtures), amber perlite (homogeneous composition), glassy and other varieties. In terms of texture, there are massive, streaky, brecciated and pumiceous perlites.
Crude perlite is quarried and then crushed and fractionated. The prduced product with the grain size of 3.0 to 0.14 mm is ready be supplied to trade market. This form of perlite material is subject to subsequent expansion. Perlite is the most multipurpose – universal material.