Nature's Guide Expanded Shale

A soil amendment that has clay-busting and water-wise properties. It loosens up the soil and holds moisture. Expanded Shale is a sedimentary rock: hardened layers of clay, silt and other minerals, essentially very old mud. When crushed and fired in a rotary kiln at 2,000 degrees fahrenheit, tiny air spaces in the shale expand. The result, expanded or vitrifed shale, it is a lightweight, gray gravel. It’s a second cousin to the better known silicate soil amendments vermiculite and perlite.