Decomposed granite

Decomposed granite is granite rock that has weathered to the point where it readily fractures into smaller pieces of weaker rock. Further weathering yields material that easily crumbles into gravel-sized particles known as "grus", which may then break down further to produce a mixture of clay and silica sand or silt particles. Different granite types weather at different rates, so their likelihood of producing decomposed granite varies. Its practical uses include incorporation into paving materials for roads and driveways, residential gardening materials in arid environments, and various types of walkways and heavy-use paths in parks. Decomposed granite is available in various colours, originating from the natural spectrum of granite hues from different quarry sources. An admixture of other natural or synthetic materials can broaden the range of decomposed granite properties.