Hydrated, naturally-occurring volcanic glass
Its unique structure consists of numerous concentric layers, similar to the layers of an onion. When heated above 1600º F, the water bound in the rock vaporizes, causing perlite to expand up to 20 times its original size. The resulting product has an extremely low bulk density. Celatom® Perlite's inert composition meets most purity requirements and is effective for a wide range of filtration applications, especially those requiring high throughput and moderate clarity.