Celatom® Perlite is a hydrated, naturally-occurring volcanic rock. Its unique structure consists of numerous concentric layers, similar to the layers in an onion. Its natural color ranges from light pearl gray to dark gray. The distinguishing feature which sets perlite apart from other volcanic siliceous rocks is that when heated above 1600°F, it expands up to 20 times its original size. The expansion is due to the presence of water (nearly 5%) trapped in the crude ore. When processed at proper temperature, the crude ore "pops" in a manner similar to popcorn. During the material processing, the combined water vaporizes, creating countless tiny bubbles that account for the amazing light weight and other exceptional properties of Celatom perlite. Perlite filter aids are available in a full range of grades with specific permeabilities which produce varying degrees of clarification.
