Difference between Rock and Soil music: Soil and rock are composed of similar materials, but differ in their structure. Rock (in this instance massive bedrock or floating rock formations) has properties defined by the existing failure surfaces - i.e. cracks in the rock formation. Typical rock formations have one or more series of parallel cracks or fracture planes that define the capacity of the rock to support given loads. Soils, on the other hand, consist of weathered rock particles. The difference between rock and soil will depend on the scope of your analysis. For example, a rock that has small particles in the cracks noted above may perform more like a soil, while a high gravel- or cobble-containing soil mass may perform more like rock that a soil.