Aurora Innovations Precision Perlite Coarse is created naturally by the hydration of obsidian. The obsidian ore is superheated in a state-of-the-art furnace and popped like popcorn, then filtered through many different screens to give Aurora Innovations extreme control over the exact size and consistency of the perlite. Coarse Perlite has substantial surface area and the ability to retain a balance of air and moisture. This amazing, versatile and lightweight media can be used alone or as a component of hydroponic mixes, or to amend potting soil for more aeration. More oxygen in the root zone can be tremendously beneficial for plant vigor, growth rates and yields.