Decomposed granite is like gravel, but finer and generally more stable. It’s formed from the natural weathering and erosion of solid granite, a tough, hard, igneous rock. The DG sold as landscaping material is typically composed of fine 3/8-inch (or smaller) particles; some may be no bigger than a grain of sand. It makes a great base for patios and walkways by keeping stones from sinking into the earth or becoming off balance.
Natural DG is used as a mulch material and can be spread around trees and garden beds much like wood mulch. It will continue to weather after it is put in place and provides nutrients to surrounding soil and plants. It lasts longer than most other mulch materials and will not attract pests.