Soil Mender Lava Sand is a rock powder which is used to improve the physical characteristics of the soil. Lava Sand has a cellular structure that provides aeration and porosity to the soil. Lava Sand helps retain the right amount of moisture in the soil, is durable, and resists degradation. High energy soil amendment that improves aeration and porosity of the soil. Increases paramagnetism in the soil, which results in increased plant vigor and production.