Decomposed granite is a relatively inexpensive, casual paving material which can be used for many different kinds of hardscapes. As granite rock decomposes over millions of years it becomes what is commonly known as decomposed granite gravel. It packs well yet allows water to drain through. It is high in trace minerals, very organic and environmentally safe. It is commonly used for walkways or driveways, as mulch, or as a paver/stone base.