Class 5 gravel is a type of gravel that is commonly used for road and driveway material, as well as for a base under blacktop. It is made by a crushing and screening process and is a mixture of sand, rock, and clay. Class 5 gravel is known for packing well and is typically a common brown color. It is important to note that Class 5 gravel is not a specific type of rock, but rather a classification based on its size and composition.