Some things in CG look harder than they actually are. This is the case with creating a nice looking sand or gravel scene for render. You could simulate the look and feel of sand using solvers and particles, scattering tools, or there is an easier way too. Showing how it is done in Cinema 4D is Niko Schatz.
Niko offers a look into creating a great looking scene that has sand or gravel in it, using both the Cinema 4D Physical Renderer and again in Octane. Having the proper maps can take you a long way. Niko uses a diffuse image, and from that has created a specular, ambient occlusion and displacement and normal maps. If you want to follow along, Niko makes all of the maps available for download on his site. It is interesting to watch the small workflow differences with the two renderers within cinema 4d.