Sphericity scale

The sphericity scale is a measure used by geologists and geographers which measures the sphericity of a stone or particle. A geographer can determine from a stone's sphericity whether or not significant erosion has taken place in its location (such as a river). The more the stone resembles a sphere, the more erosion it has probably witnessed. This scale should not be confused with the scale which measures the shape of the stone and how angular it is.