Perlite is heat-expanded volcanic rock, and it is the world’s premier organic aeration and drainage agent
When the rock reaches temperatures of 850–900 °C, perlite softens (because it is a type of glass). Water trapped in the structure of the material vaporizes and escapes, and this causes the expansion of the material. When used as an amendment it has high permeability / low water retention and helps prevent soil compaction. Our perlite is made in Colorado.