Sourced from Northern Arizona our 1/2 cubic foot box of Black Lava Sand is screened at 3/16” minus and consists of more than 50% fine sand granules. Lava is a porous light weight rock consisting primarily of Plagioclase, Olivine, and Augite. It is primarily used in gardening as a light weight aggregate amendment to loosen and aerate the soil. Its porous structure will help break up heavy clay soil to allow drainage while providing moisture retention.