There are many commercial applications for perlite because of  its low density and relatively low price :
    In horticulture, perlite can be used as a soil amendment or alone as a medium for hydroponics or for starting cuttings.it helps prevent water loss and soil compaction.When used as an amendment.
   It is used in lightweight plasters and insulation, mortars, ceiling tiles and filter aids in the construction and manufacturing fields;
   Perlite is also used in foundries, cryogenic insulation, as a lightweight aggregate in mortar (firestop) and in ceramics as a clay additive. It is also used by the explosive industry.

Perlite is an excellent filter aid. It is used extensively in Australia and New Zealand as an alternative to diatomaceous earth. The popularity of Perlite usage in this application is growing considerably worldwide.